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 (
    87709, 87721, 87723, 87735, 88694, 88695, 
    88741, 88742, 88149, 88587, 84241, 
    87234, 87235, 87236, 87239, 87240, 
    87241, 87244, 87245, 87246, 87249, 
    87250, 87251, 84240, 88588, 84239, 
    84238, 84254, 84259, 87577, 87592, 
    87607, 88788, 90054, 90056, 90057, 
    84252, 84253, 84257, 84258, 87575, 
    87576, 87590, 87591, 87605, 87606, 
    88786, 88787
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00095

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 (87709,87721,87723,87735,88694,88695,88741,88742,88149,88587,84241,87234,87235,87236,87239,87240,87241,87244,87245,87246,87249,87250,87251,84240,88588,84239,84238,84254,84259,87577,87592,87607,88788,90054,90056,90057,84252,84253,84257,84258,87575,87576,87590,87591,87605,87606,88786,88787)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}