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 (
    4603, 4606, 4623, 4629, 4625, 4605, 6273, 
    4572, 4577, 4578, 4630, 4631, 4556, 
    4607, 4633, 4634, 4576, 4575, 4627, 
    4608, 4622, 4619, 4632, 4626, 4628, 
    4620, 4580, 6265, 4621, 4609, 6285, 
    6322, 6284, 6283, 6326, 6324, 6325, 
    6295, 6294, 6287
  ) 
  AND cscart_product_descriptions.lang_code = 'ar'

Query time 0.00121

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 (4603,4606,4623,4629,4625,4605,6273,4572,4577,4578,4630,4631,4556,4607,4633,4634,4576,4575,4627,4608,4622,4619,4632,4626,4628,4620,4580,6265,4621,4609,6285,6322,6284,6283,6326,6324,6325,6295,6294,6287)) 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"
      ]
    }
  }
}