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 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    95312, 95313, 95737, 95755, 95765, 95787, 
    95820, 98230, 98231, 98232, 98324, 
    98326, 98502, 99137, 99138, 99146, 
    99147, 99155, 99186, 99188, 99195, 
    99217, 99241, 99267, 100393, 100394
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00088

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "11.72"
    },
    "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": 26,
      "rows_produced_per_join": 26,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "9.12",
        "eval_cost": "2.60",
        "prefix_cost": "11.72",
        "data_read_per_join": "99K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (95312,95313,95737,95755,95765,95787,95820,98230,98231,98232,98324,98326,98502,99137,99138,99146,99147,99155,99186,99188,99195,99217,99241,99267,100393,100394)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}