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 (
    94998, 94999, 95000, 95001, 95002, 95003, 
    95004, 95005, 95006, 95007, 95008, 
    95009, 95010, 95011, 95012, 95013, 
    95014, 95015, 95016, 95017, 95018, 
    95019, 95020, 95021, 95022, 95023, 
    95024, 95025, 95026, 95027
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00076

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 (94998,94999,95000,95001,95002,95003,95004,95005,95006,95007,95008,95009,95010,95011,95012,95013,95014,95015,95016,95017,95018,95019,95020,95021,95022,95023,95024,95025,95026,95027)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
94998
94999
95000
95001
95002
95003
95004
95005
95006
95007
95008
95009
95010
95011
95012
95013
95014
95015
95016
95017
95018
95019
95020
95021
95022
95023
95024
95025
95026
95027