SELECT 
  pfv.variant_id, 
  pfv.position, 
  pfvd.variant 
FROM 
  cscart_product_feature_variants AS pfv 
  INNER JOIN cscart_product_feature_variant_descriptions AS pfvd ON pfv.variant_id = pfvd.variant_id 
  AND pfvd.lang_code = 'en' 
WHERE 
  pfv.variant_id IN (
    2216, 2215, 2214, 2213, 2212, 2787, 2789, 
    2790, 2791, 2788, 2803, 2804, 2805, 
    2806, 2807, 2808, 1600, 1560, 1596, 
    2315, 1912, 2077, 1559
  )

Query time 0.00109

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "24.16"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id"
          ],
          "key_length": "3",
          "rows_examined_per_scan": 23,
          "rows_produced_per_join": 23,
          "filtered": "100.00",
          "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`pfv`.`variant_id` in (2216,2215,2214,2213,2212,2787,2789,2790,2791,2788,2803,2804,2805,2806,2807,2808,1600,1560,1596,2315,1912,2077,1559))",
          "cost_info": {
            "read_cost": "13.81",
            "eval_cost": "2.30",
            "prefix_cost": "16.11",
            "data_read_per_join": "26K"
          },
          "used_columns": [
            "variant_id",
            "position"
          ]
        }
      },
      {
        "table": {
          "table_name": "pfvd",
          "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": 23,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "5.75",
            "eval_cost": "2.30",
            "prefix_cost": "24.16",
            "data_read_per_join": "69K"
          },
          "used_columns": [
            "variant_id",
            "variant",
            "lang_code"
          ]
        }
      }
    ]
  }
}