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 (
    85644, 85580, 86863, 92151, 92152, 92153, 
    92353, 92354, 92355, 92356, 91893, 
    91894, 91895, 92337, 92338, 92339, 
    92340, 90824, 90825, 91839, 87232, 
    87233, 87237, 87238, 87242, 87243, 
    87247, 87248, 92450, 92451, 92452, 
    92453, 92454, 92455, 92456, 91838, 
    91837, 92500, 85039, 84251, 84256, 
    87580, 87595, 87610, 88791, 87370, 
    89609, 89610
  ) 
  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 (85644,85580,86863,92151,92152,92153,92353,92354,92355,92356,91893,91894,91895,92337,92338,92339,92340,90824,90825,91839,87232,87233,87237,87238,87242,87243,87247,87248,92450,92451,92452,92453,92454,92455,92456,91838,91837,92500,85039,84251,84256,87580,87595,87610,88791,87370,89609,89610)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}