N1ql indexing sequence

SQL++
15

I am still confused. and I just test above N1QL,
for

CREATE INDEX ix1 on default(inKey,eualKey);

the part of explain shows

              {
                "exact": true,
                "range": [
                  {
                    "high": "8198",
                    "inclusion": 3,
                    "low": "8198"
                  },
                  {
                    "high": "\"xyz\"",
                    "inclusion": 3,
                    "low": "\"xyz\""
                  }
                ]
              },
              {
                "exact": true,
                "range": [
                  {
                    "high": "8199",
                    "inclusion": 3,
                    "low": "8199"
                  },
                  {
                    "high": "\"xyz\"",
                    "inclusion": 3,
                    "low": "\"xyz\""
                  }
                ]
              },
              {
                "exact": true,
                "range": [
                  {
                    "high": "8200",
                    "inclusion": 3,
                    "low": "8200"
                  },
                  {
                    "high": "\"xyz\"",
                    "inclusion": 3,
                    "low": "\"xyz\""
                  }
                ]
              }
            ]

and for

CREATE INDEX ix1 on default(eualKey,inKey);

the part of explain shows

              {
                "exact": true,
                "range": [
                  {
                    "high": "\"xyz\"",
                    "inclusion": 3,
                    "low": "\"xyz\""
                  },
                  {
                    "high": "8199",
                    "inclusion": 3,
                    "low": "8199"
                  }
                ]
              },
              {
                "exact": true,
                "range": [
                  {
                    "high": "\"xyz\"",
                    "inclusion": 3,
                    "low": "\"xyz\""
                  },
                  {
                    "high": "8200",
                    "inclusion": 3,
                    "low": "8200"
                  }
                ]
              }
            ]

nothing was pruned?