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 (
    94393, 94394, 94395, 94396, 94397, 94398, 
    94399, 94400, 94401, 94402, 94403, 
    94404, 94405, 94406, 94407, 94408, 
    94409, 94410, 94411, 94412, 94413, 
    94414, 94415, 94416
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "10.82"
    },
    "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": 24,
      "rows_produced_per_join": 24,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "8.42",
        "eval_cost": "2.40",
        "prefix_cost": "10.82",
        "data_read_per_join": "91K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (94393,94394,94395,94396,94397,94398,94399,94400,94401,94402,94403,94404,94405,94406,94407,94408,94409,94410,94411,94412,94413,94414,94415,94416)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
94393
94394
94395
94396
94397
94398
94399
94400
94401
94402
94403
94404
94405
94406
94407
94408
94409
94410
94411
94412
94413
94414
94415
94416