Simple Select query taking longer time

Hi Team,

I am executing below query which is taking near about 11 sec to execute.

SELECT
  *
    FROM `mybucket`
    WHERE type="history" AND ( event IN ["modified","rejected","approved","created"] )
    ORDER BY timestamp desc
    LIMIT 20
    OFFSET 0;

I have added index CREATE INDEX adv_event_type_test ON `mybucket`(`event`,`timestamp` DESC) WHERE (`type` = 'history');

Refer the below output of Plan text tab:

{
  "#operator": "Sequence",
  "#stats": {
    "#phaseSwitches": 1,
    "execTime": "5.885µs"
  },
  "~children": [
    {
      "#operator": "Authorize",
      "#stats": {
        "#phaseSwitches": 3,
        "execTime": "9.775µs",
        "servTime": "16.872617ms"
      },
      "privileges": {
        "List": [
          {
            "Target": "default:mybucket",
            "Priv": 7
          }
        ]
      },
      "~child": {
        "#operator": "Sequence",
        "#stats": {
          "#phaseSwitches": 1,
          "execTime": "5.09µs"
        },
        "~children": [
          {
            "#operator": "Sequence",
            "#stats": {
              "#phaseSwitches": 1,
              "execTime": "3.37µs"
            },
            "~children": [
              {
                "#operator": "IndexScan3",
                "#stats": {
                  "#itemsOut": 93784,
                  "#phaseSwitches": 375139,
                  "execTime": "211.108256ms",
                  "kernTime": "10.421695486s",
                  "servTime": "37.78984ms"
                },
                "index": "adv_event_type_test",
                "index_id": "989a75359b496459",
                "index_projection": {
                  "primary_key": true
                },
                "keyspace": "mybucket",
                "namespace": "default",
                "spans": [
                  {
                    "exact": true,
                    "range": [
                      {
                        "high": "\"approved\"",
                        "inclusion": 3,
                        "low": "\"approved\""
                      }
                    ]
                  },
                  {
                    "exact": true,
                    "range": [
                      {
                        "high": "\"created\"",
                        "inclusion": 3,
                        "low": "\"created\""
                      }
                    ]
                  },
                  {
                    "exact": true,
                    "range": [
                      {
                        "high": "\"modified\"",
                        "inclusion": 3,
                        "low": "\"modified\""
                      }
                    ]
                  },
                  {
                    "exact": true,
                    "range": [
                      {
                        "high": "\"rejected\"",
                        "inclusion": 3,
                        "low": "\"rejected\""
                      }
                    ]
                  }
                ],
                "using": "gsi",
                "#time_normal": "00:00.248",
                "#time_absolute": 0.248898096
              },
              {
                "#operator": "Fetch",
                "#stats": {
                  "#itemsIn": 93784,
                  "#itemsOut": 93784,
                  "#phaseSwitches": 386863,
                  "execTime": "265.658084ms",
                  "kernTime": "1.535227126s",
                  "servTime": "8.907075461s"
                },
                "keyspace": "mybucket",
                "namespace": "default",
                "#time_normal": "00:09.172",
                "#time_absolute": 9.172733545
              },
              {
                "#operator": "Sequence",
                "#stats": {
                  "#phaseSwitches": 1,
                  "execTime": "2.175µs"
                },
                "~children": [
                  {
                    "#operator": "Filter",
                    "#stats": {
                      "#itemsIn": 93784,
                      "#itemsOut": 93784,
                      "#phaseSwitches": 375139,
                      "execTime": "6.603747692s",
                      "kernTime": "4.104305653s"
                    },
                    "condition": "(((`mybucket`.`type`) = \"history\") and ((`mybucket`.`event`) in [\"modified\", \"rejected\", \"approved\", \"created\"]))",
                    "#time_normal": "00:06.603",
                    "#time_absolute": 6.603747692
                  },
                  {
                    "#operator": "InitialProject",
                    "#stats": {
                      "#itemsIn": 93784,
                      "#itemsOut": 93784,
                      "#phaseSwitches": 375139,
                      "execTime": "76.940801ms",
                      "kernTime": "10.631129494s"
                    },
                    "result_terms": [
                      {
                        "expr": "self",
                        "star": true
                      }
                    ],
                    "#time_normal": "00:00.076",
                    "#time_absolute": 0.07694080099999999
                  }
                ],
                "#time_normal": "00:00.000",
                "#time_absolute": 0.000002175
              }
            ],
            "#time_normal": "00:00.000",
            "#time_absolute": 0.00000337
          },
          {
            "#operator": "Order",
            "#stats": {
              "#itemsIn": 93784,
              "#itemsOut": 20,
              "#phaseSwitches": 187593,
              "execTime": "659.574576ms",
              "kernTime": "10.048613624s"
            },
            "limit": "20",
            "sort_terms": [
              {
                "desc": true,
                "expr": "(`mybucket`.`timestamp`)"
              }
            ],
            "#time_normal": "00:00.659",
            "#time_absolute": 0.659574576
          },
          {
            "#operator": "Limit",
            "#stats": {
              "#itemsIn": 20,
              "#itemsOut": 20,
              "#phaseSwitches": 41,
              "execTime": "12.957µs"
            },
            "expr": "20",
            "#time_normal": "00:00.000",
            "#time_absolute": 0.000012957000000000001
          },
          {
            "#operator": "FinalProject",
            "#stats": {
              "#itemsIn": 20,
              "#itemsOut": 20,
              "#phaseSwitches": 61,
              "execTime": "21.482µs",
              "kernTime": "2.997041ms"
            },
            "#time_normal": "00:00.000",
            "#time_absolute": 0.000021482
          }
        ],
        "#time_normal": "00:00.000",
        "#time_absolute": 0.0000050899999999999995
      },
      "#time_normal": "00:00.016",
      "#time_absolute": 0.016882392000000003
    },
    {
      "#operator": "Stream",
      "#stats": {
        "#itemsIn": 20,
        "#itemsOut": 20,
        "#phaseSwitches": 43,
        "execTime": "2.96426ms",
        "kernTime": "10.725225582s"
      },
      "#time_normal": "00:00.002",
      "#time_absolute": 0.00296426
    }
  ],
  "~versions": [
    "6.5.0-N1QL",
    "6.5.1-6299-enterprise"
  ],
  "#time_normal": "00:00.000",
  "#time_absolute": 0.0000058849999999999996
}

When I am removing ORDER BY clause it is executing within 300ms.

Is there any way to optimised this query so that this will execute within 300ms without removing order by clause., any help is appreciated.

Thanks in Advance!