How to query keyword nested field that can be an integer values in ElasticSearch?

This is example of field in ES document. How can i query 'prices.value' that can be only integers?

In this case, value is "150.99" and can fully be converted to integer. But sometimes in can be a text something like "value": "a lot" and i want to exclude document with this values.

 "prices": [
     {
      "currency": "RUR",
      "id_offer": 605994811,
       "id_prcdoc": 42172,
        "id_prcknd": 20859,
         "info": {},
         "min_order": null,
         "sell_by": null,
         "value": "150.99"}]

Index of this field:

"prices": {
        "type": "nested",
        "properties": {
          "currency": {
            "type": "keyword"
          },
          "id_offer": {
            "type": "integer"
          },
          "id_prcdoc": {
            "type": "integer"
          },
          "id_prcknd": {
            "type": "integer"
          },
          "min_order": {
            "type": "keyword"
          },
          "sell_by": {
            "type": "keyword"
          },
          "value": {
            "type": "keyword",
            "index": false
          }
        }
      }

And sometimes it 'value' field can be '0.00' and probably i want to exclude this values to..

You can use painless script to check if value can be converted to number.

{
  "query": {
    "bool": {
      "must": [
        {
          "nested": {
            "path": "prices",
            "query": {
              "script": {
                "script": "if(doc['prices.value'].size()==0){return false;}if(doc['prices.value'].value=='0.00'){return false;}try{ Double.parseDouble(doc['prices.value'].value); return true;} catch(Exception e){return false;} "
              }
            },
            "inner_hits": {}
          }
        }
      ]
    }
  }
}

Result will be in inner_hit. Since scripts are slow it is better to resolve it while indexing . Another field can we created which will have value only if it is price value is number, and in query this field can be used

EDIT:

{
  "query": {
    "bool": {
      "must": [
        {
          "nested": {
            "path": "prices",
            "query": {
              "bool": {
                "must": [
                  {
                    "regexp": {
                      "prices.value": "[1-9][0-9]*.*[0-9]*"
                    }
                  }
                ]
              }
            },
            "inner_hits": {}
          }
        }
      ]
    }
  }
}