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 (
    92942, 92943, 92944, 92945, 93016, 93017, 
    93018, 93019, 93020, 93021, 93022, 
    93023, 93024, 93025, 93026, 93027, 
    93028, 93029, 93030, 93031, 93032, 
    93033, 93034, 93035, 93036, 93037, 
    93038, 93039, 93040, 93041
  ) 
  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 (92942,92943,92944,92945,93016,93017,93018,93019,93020,93021,93022,93023,93024,93025,93026,93027,93028,93029,93030,93031,93032,93033,93034,93035,93036,93037,93038,93039,93040,93041)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
92942
92943
92944
92945
93016
93017
93018
93019
93020
93021
93022
93023
93024
93025
93026
93027
93028
93029
93030
93031
93032
93033
93034
93035
93036
93037
93038
93039
93040
93041