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 (
    89712, 89713, 89670, 88106, 88118, 88130, 
    88264, 88273, 88274, 88270, 88302, 
    88303, 89708, 89709, 89666, 88268, 
    88269, 89669, 89705, 89662, 89672, 
    89673, 88267, 89667, 89668, 89710, 
    89711, 88348, 88349, 88350, 89665, 
    88300, 88301, 88265, 88266, 88272, 
    89706, 89707, 88344, 88345, 88346, 
    88347, 89663, 89664, 89671, 89701, 
    89702, 88105
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00097

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "data_read_per_join": "183K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (89712,89713,89670,88106,88118,88130,88264,88273,88274,88270,88302,88303,89708,89709,89666,88268,88269,89669,89705,89662,89672,89673,88267,89667,89668,89710,89711,88348,88349,88350,89665,88300,88301,88265,88266,88272,89706,89707,88344,88345,88346,88347,89663,89664,89671,89701,89702,88105)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}