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 = 'ar' 
WHERE 
  pfv.feature_id IN (656) 
  AND pfv.product_id IN (
    6151, 5696, 2698, 5721, 5621, 5724, 3605, 
    5944, 4951, 3155, 3834, 2737, 5892, 
    2431, 5934, 5114, 2924, 6098, 2922, 
    5703, 3603, 4894, 2702, 3649, 4962, 
    4958, 4942, 3215, 3213, 5691, 5687, 
    3552, 2805, 4915, 6025, 3150, 4976, 
    3115, 3112, 3664, 2655, 5683, 2226, 
    3811, 6054, 3153, 3377, 2522, 2719, 
    6041, 3385, 5948, 3831, 3289, 3382, 
    6093, 6194
  ) 
  AND pfv.lang_code = 'ar'

Query time 0.00710

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "34.32"
    },
    "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": 59,
          "rows_produced_per_join": 59,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "6.74",
            "eval_cost": "5.90",
            "prefix_cost": "12.64",
            "data_read_per_join": "45K"
          },
          "used_columns": [
            "feature_id",
            "product_id",
            "variant_id",
            "lang_code"
          ],
          "attached_condition": "((`softwarepirmam_hewadelivard_cscart_4`.`pfv`.`feature_id` = 656) and (`softwarepirmam_hewadelivard_cscart_4`.`pfv`.`product_id` in (6151,5696,2698,5721,5621,5724,3605,5944,4951,3155,3834,2737,5892,2431,5934,5114,2924,6098,2922,5703,3603,4894,2702,3649,4962,4958,4942,3215,3213,5691,5687,3552,2805,4915,6025,3150,4976,3115,3112,3664,2655,5683,2226,3811,6054,3153,3377,2522,2719,6041,3385,5948,3831,3289,3382,6093,6194)) and (`softwarepirmam_hewadelivard_cscart_4`.`pfv`.`lang_code` = 'ar'))"
        }
      },
      {
        "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": 2,
          "filtered": "5.00",
          "cost_info": {
            "read_cost": "14.75",
            "eval_cost": "0.30",
            "prefix_cost": "33.29",
            "data_read_per_join": "3K"
          },
          "used_columns": [
            "variant_id",
            "feature_id",
            "position"
          ],
          "attached_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`fv`.`feature_id` = 656)"
        }
      },
      {
        "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": 2,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.74",
            "eval_cost": "0.30",
            "prefix_cost": "34.32",
            "data_read_per_join": "8K"
          },
          "used_columns": [
            "variant_id",
            "variant",
            "lang_code"
          ]
        }
      }
    ]
  }
}