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 (
    94545, 94546, 94547, 94548, 94549, 94550, 
    94551, 94552, 94553, 94554, 94555, 
    94556, 94557, 94558, 94559, 94560, 
    94561, 94562, 94563, 94564, 94565, 
    94566, 94567, 94568, 94569, 94570, 
    94571, 94572, 94573, 94574, 94575, 
    94576, 94577, 94578, 94579, 94580, 
    94581, 94582, 94583, 94584, 94585, 
    94586, 94587, 94588, 94827, 94828, 
    94829, 94830
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00098

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.62"
    },
    "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": "16.82",
        "eval_cost": "4.80",
        "prefix_cost": "21.62",
        "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 (94545,94546,94547,94548,94549,94550,94551,94552,94553,94554,94555,94556,94557,94558,94559,94560,94561,94562,94563,94564,94565,94566,94567,94568,94569,94570,94571,94572,94573,94574,94575,94576,94577,94578,94579,94580,94581,94582,94583,94584,94585,94586,94587,94588,94827,94828,94829,94830)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
94545
94546
94547
94548
94549
94550
94551
94552
94553
94554
94555
94556
94557
94558
94559
94560
94561
94562
94563
94564
94565
94566
94567
94568
94569
94570
94571
94572
94573
94574
94575
94576
94577
94578
94579
94580
94581
94582
94583
94584
94585
94586
94587
94588
94827
94828
94829
94830