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 (
    96221, 96222, 96223, 96224, 96225, 96226, 
    96227, 96228, 96229, 96230, 96231, 
    96232, 96233, 96234, 96235, 96236, 
    96237, 96238, 96239, 96240, 96241, 
    96242, 96243, 96244, 96334, 96336, 
    96338, 96340, 98722, 98723, 98724, 
    98725, 98726, 98727, 98728, 98729, 
    98730, 98731, 98732, 98733, 98734, 
    98735, 98736, 98737, 98750, 98751, 
    98752, 98753
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00104

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 (96221,96222,96223,96224,96225,96226,96227,96228,96229,96230,96231,96232,96233,96234,96235,96236,96237,96238,96239,96240,96241,96242,96243,96244,96334,96336,96338,96340,98722,98723,98724,98725,98726,98727,98728,98729,98730,98731,98732,98733,98734,98735,98736,98737,98750,98751,98752,98753)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
96221
96222
96223
96224
96225
96226
96227
96228
96229
96230
96231
96232
96233
96234
96235
96236
96237
96238
96239
96240
96241
96242
96243
96244
96334
96336
96338
96340
98722
98723
98724
98725
98726
98727
98728
98729
98730
98731
98732
98733
98734
98735
98736
98737
98750
98751
98752
98753