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 (
    2395, 4279, 4294, 2399, 1665, 5899, 2201, 
    5934, 4193, 2393, 2172, 2171, 1664, 
    4058, 4226, 4275, 4195, 2175, 2177, 
    4225, 2400, 4239, 4191, 2179, 2183, 
    4233, 2176, 4410, 4209, 4429, 4411, 
    4451, 2180, 2178, 2170, 2181, 2182, 
    4255, 2173, 4244
  ) 
  AND cscart_product_descriptions.lang_code = 'ar'

Query time 0.00136

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "28.33"
    },
    "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": 40,
      "rows_produced_per_join": 40,
      "filtered": "100.00",
      "index_condition": "((`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_descriptions`.`product_id` in (2395,4279,4294,2399,1665,5899,2201,5934,4193,2393,2172,2171,1664,4058,4226,4275,4195,2175,2177,4225,2400,4239,4191,2179,2183,4233,2176,4410,4209,4429,4411,4451,2180,2178,2170,2181,2182,4255,2173,4244)) and (`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_descriptions`.`lang_code` = 'ar'))",
      "cost_info": {
        "read_cost": "24.33",
        "eval_cost": "4.00",
        "prefix_cost": "28.33",
        "data_read_per_join": "182K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "unit_name"
      ]
    }
  }
}