SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    466, 467, 468, 469, 470, 471, 472, 473, 
    474, 475, 476, 477, 478, 479, 480, 481, 
    482, 483, 484, 485, 486, 487, 488, 489, 
    490, 491, 492, 493, 494, 495, 496, 497, 
    498, 499, 500, 501, 502, 503, 504, 505, 
    506, 507, 508, 509, 510, 511, 512, 513, 
    514, 515
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00072

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "120.01"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 50,
      "rows_produced_per_join": 50,
      "filtered": "100.00",
      "index_condition": "((`atulecarter_atul_demo2`.`cscart_product_descriptions`.`product_id` in (466,467,468,469,470,471,472,473,474,475,476,477,478,479,480,481,482,483,484,485,486,487,488,489,490,491,492,493,494,495,496,497,498,499,500,501,502,503,504,505,506,507,508,509,510,511,512,513,514,515)) and (`atulecarter_atul_demo2`.`cscart_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "110.01",
        "eval_cost": "10.00",
        "prefix_cost": "120.01",
        "data_read_per_join": "228K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "unit_name"
      ]
    }
  }
}