ElasticSearch Query with function score is running more than 5 times slower

Elastic Stack Elasticsearch
1

Here is my query without function score:

{
  "from": 200,
  "size": 25,
  "query": {
    "bool": {
    "filter": {
          "bool": {
            "must": [
              {
                "nested": {
                  "query": {
                    "terms": {
                      "cotypes.id": [
                        199
                      ]
                    }
                  },
                  "path": "cotypes"
                }
              },
              {
                "range": {
                  "relevance": {
                    "from": 6,
                    "to": null,
                    "include_lower": true,
                    "include_upper": true
                  }
                }
              }
            ],
            "must_not": {
              "terms": {
                "ontologyId": [
                  1314696,
                  1314691
                ]
              }
            }
          }
        },
      "must": {
        "match": {
          "name.nameStandard": {
            "query": "john smith",
            "type": "boolean",
            "boost": 10
          }
        }
      }
    }
  }
}

This query return the response in ~250ms.

But I need to add some boost factor for improve the default scoring. I modified the query to use the function score, but after that query taking too long (~1300ms)

Here is the function score query:

{
  "from": 200,
  "size": 25,
  "query": {
  "function_score": {
    "query": {
    "bool": {
    "filter": {
          "bool": {
            "must": [
              {
                "nested": {
                  "query": {
                    "terms": {
                      "cotypes.id": [
                        199
                      ]
                    }
                  },
                  "path": "cotypes"
                }
              },
              {
                "range": {
                  "relevance": {
                    "from": 6,
                    "to": null,
                    "include_lower": true,
                    "include_upper": true
                  }
                }
              }
            ],
            "must_not": {
              "terms": {
                "ontologyId": [
                  1314696,
                  1314691
                ]
              }
            }
          }
        },
      "must": {
        "match": {
          "name.nameStandard": {
            "query": "john smith",
            "type": "boolean",
            "boost": 10
          }
        }
      }
    }
    },
    "functions": [
      {
        "script_score": {
          "script": {
            "file": "calculate-score",
            "lang": "groovy",
            "params": {
              "relevance_boost": 0.5
            }
          }
        }
      }
    ],
    "boost_mode": "sum"
  }
}
}

calculate-score.groovy script given below:

def penalize = 1
def penalizeClassDict = [
    '226': 0.25,
    '14106': 0.25,
    '656': 0.25
   ]
for (item in doc['classIds'].values)
{
    if(penalizeClassDict.containsKey(item.toString()))
        penalize = penalize * penalizeClassDict[ item.toString()]
}
_score + (pow(doc['relevance'].value, relevance_boost)) * penalize

Please help me to make the query perform better!

Thank you in advance!