SELECT 
  pfv.feature_id, 
  pfv.product_id, 
  pfv.variant_id, 
  fv.position, 
  fvd.variant 
FROM 
  cscart_product_features_values AS pfv 
  INNER JOIN cscart_product_feature_variants AS fv ON pfv.feature_id = fv.feature_id 
  AND pfv.variant_id = fv.variant_id 
  INNER JOIN cscart_product_feature_variant_descriptions AS fvd ON pfv.variant_id = fvd.variant_id 
  AND fvd.lang_code = 'en' 
WHERE 
  pfv.feature_id IN (771, 656, 779) 
  AND pfv.product_id IN (
    11306, 11446, 11472, 11508, 11086, 11337, 
    11348, 11411, 11531, 11477, 11430, 
    11479, 11600, 11362, 11414, 11520, 
    11535, 11633, 11390, 11399, 11530, 
    11236, 11462, 11136, 11352, 11458
  ) 
  AND pfv.lang_code = 'en'

Query time 0.00374

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "52.32"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY",
            "fl",
            "variant_id",
            "lang_code",
            "product_id",
            "fpl",
            "idx_product_feature_variant_id"
          ],
          "key": "idx_product_feature_variant_id",
          "used_key_parts": [
            "product_id",
            "feature_id",
            "lang_code"
          ],
          "key_length": "12",
          "rows_examined_per_scan": 85,
          "rows_produced_per_join": 85,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "9.60",
            "eval_cost": "8.50",
            "prefix_cost": "18.10",
            "data_read_per_join": "65K"
          },
          "used_columns": [
            "feature_id",
            "product_id",
            "variant_id",
            "lang_code"
          ],
          "attached_condition": "((`softwarepirmam_hewadelivard_cscart_4`.`pfv`.`feature_id` in (771,656,779)) and (`softwarepirmam_hewadelivard_cscart_4`.`pfv`.`product_id` in (11306,11446,11472,11508,11086,11337,11348,11411,11531,11477,11430,11479,11600,11362,11414,11520,11535,11633,11390,11399,11530,11236,11462,11136,11352,11458)) and (`softwarepirmam_hewadelivard_cscart_4`.`pfv`.`lang_code` = 'en'))"
        }
      },
      {
        "table": {
          "table_name": "fv",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY",
            "feature_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id"
          ],
          "key_length": "3",
          "ref": [
            "softwarepirmam_hewadelivard_cscart_4.pfv.variant_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 12,
          "filtered": "15.04",
          "cost_info": {
            "read_cost": "21.25",
            "eval_cost": "1.28",
            "prefix_cost": "47.85",
            "data_read_per_join": "14K"
          },
          "used_columns": [
            "variant_id",
            "feature_id",
            "position"
          ],
          "attached_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`fv`.`feature_id` = `softwarepirmam_hewadelivard_cscart_4`.`pfv`.`feature_id`)"
        }
      },
      {
        "table": {
          "table_name": "fvd",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id",
            "lang_code"
          ],
          "key_length": "9",
          "ref": [
            "softwarepirmam_hewadelivard_cscart_4.pfv.variant_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 12,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "3.20",
            "eval_cost": "1.28",
            "prefix_cost": "52.32",
            "data_read_per_join": "38K"
          },
          "used_columns": [
            "variant_id",
            "variant",
            "lang_code"
          ]
        }
      }
    ]
  }
}