SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    5032, 5028, 5030, 5029, 5036, 5461, 5458, 
    5328, 5047, 5365, 5033, 5456, 5596, 
    5367, 5500, 5054, 5335, 5504, 5506, 
    5464, 5508, 6081, 6144, 6083, 6189, 
    6145, 5644, 6297, 6190, 6276, 6303, 
    6260, 6305, 6274, 6301, 6824, 6825
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00117

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "26.20"
    },
    "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": 37,
      "rows_produced_per_join": 37,
      "filtered": "100.00",
      "index_condition": "((`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_descriptions`.`product_id` in (5032,5028,5030,5029,5036,5461,5458,5328,5047,5365,5033,5456,5596,5367,5500,5054,5335,5504,5506,5464,5508,6081,6144,6083,6189,6145,5644,6297,6190,6276,6303,6260,6305,6274,6301,6824,6825)) and (`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "22.50",
        "eval_cost": "3.70",
        "prefix_cost": "26.20",
        "data_read_per_join": "168K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "unit_name"
      ]
    }
  }
}