SELECT 
  pf.feature_id 
FROM 
  cscart_product_variation_group_features AS gf 
  INNER JOIN cscart_product_filters AS pf ON gf.feature_id = pf.feature_id 
WHERE 
  pf.feature_id > 0 
  AND pf.filter_id IN (10) 
LIMIT 
  1

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "1.20"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "pf",
          "access_type": "const",
          "possible_keys": [
            "PRIMARY",
            "feature_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "filter_id"
          ],
          "key_length": "3",
          "ref": [
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.00",
            "eval_cost": "0.20",
            "prefix_cost": "0.00",
            "data_read_per_join": "64"
          },
          "used_columns": [
            "filter_id",
            "feature_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "gf",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "feature_id"
          ],
          "key_length": "3",
          "ref": [
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "1.00",
            "eval_cost": "0.20",
            "prefix_cost": "1.20",
            "data_read_per_join": "104"
          },
          "used_columns": [
            "feature_id"
          ]
        }
      }
    ]
  }
}