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 (
    5326, 5316, 5344, 5356, 5359, 5400, 5103, 
    5339, 5350, 6245, 5313, 5399, 5349, 
    5352, 5358, 5201, 5307, 5348, 5337, 
    5338, 5572, 5297, 6253, 5202, 6241, 
    6207, 6220, 6243, 6553, 7516, 11255, 
    11277, 10956, 11280, 10412, 7514, 7521, 
    7515, 7519, 10954
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00179

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 (5326,5316,5344,5356,5359,5400,5103,5339,5350,6245,5313,5399,5349,5352,5358,5201,5307,5348,5337,5338,5572,5297,6253,5202,6241,6207,6220,6243,6553,7516,11255,11277,10956,11280,10412,7514,7521,7515,7519,10954)) and (`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_descriptions`.`lang_code` = 'en'))",
      "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"
      ]
    }
  }
}