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 (
    96605, 96607, 96609, 96611, 96614, 96615, 
    96620, 96621, 96622, 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, 
    97875, 97876, 97877, 97878, 97879, 
    97880, 97881, 97882, 97886, 97888, 
    98001, 98176
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00112

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 (96605,96607,96609,96611,96614,96615,96620,96621,96622,96623,96624,96678,96694,97083,97219,97220,97221,97222,97223,97224,97225,97226,97227,97567,97570,97573,97576,97577,97578,97579,97580,97582,97583,97584,97585,97586,97875,97876,97877,97878,97879,97880,97881,97882,97886,97888,98001,98176)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
96605
96607
96609
96611
96614
96615
96620
96621
96622
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
97875
97876
97877
97878
97879
97880
97881
97882
97886
97888
98001
98176