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 (
    96623, 96624, 96678, 96694, 97083, 97219, 
    97220, 97221, 97222, 97223, 97224, 
    97225, 97226, 97227, 97567, 97570, 
    97573, 97576, 97577, 97578, 97579, 
    97580, 97582, 97583, 97584, 97585, 
    97586, 97728, 97729, 97730, 97731, 
    97732, 97733, 97734, 97735, 97736, 
    97737, 97738, 97739, 97740, 97741, 
    97742, 97778, 97779, 97780, 97781, 
    97782, 97790
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00045

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 (96623,96624,96678,96694,97083,97219,97220,97221,97222,97223,97224,97225,97226,97227,97567,97570,97573,97576,97577,97578,97579,97580,97582,97583,97584,97585,97586,97728,97729,97730,97731,97732,97733,97734,97735,97736,97737,97738,97739,97740,97741,97742,97778,97779,97780,97781,97782,97790)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}