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 (
    94055, 94056, 94057, 94058, 94059, 94060, 
    94061, 94062, 94063, 94333, 94334, 
    94335, 94336, 94337, 94338, 94339, 
    94340, 94341, 94342, 94343, 94344, 
    94345, 94346, 94347, 94348, 94349, 
    94350, 94351, 94352, 94353
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00077

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (94055,94056,94057,94058,94059,94060,94061,94062,94063,94333,94334,94335,94336,94337,94338,94339,94340,94341,94342,94343,94344,94345,94346,94347,94348,94349,94350,94351,94352,94353)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
94055
94056
94057
94058
94059
94060
94061
94062
94063
94333
94334
94335
94336
94337
94338
94339
94340
94341
94342
94343
94344
94345
94346
94347
94348
94349
94350
94351
94352
94353