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 (
    93513, 93514, 93529, 93530, 93531, 93532, 
    93533, 93534, 93535, 93536, 93537, 
    93538, 93539, 93540, 93541, 93542, 
    93543, 93544, 93545, 93546, 93547, 
    93548, 93549, 93550
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00064

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 (93513,93514,93529,93530,93531,93532,93533,93534,93535,93536,93537,93538,93539,93540,93541,93542,93543,93544,93545,93546,93547,93548,93549,93550)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
93513
93514
93529
93530
93531
93532
93533
93534
93535
93536
93537
93538
93539
93540
93541
93542
93543
93544
93545
93546
93547
93548
93549
93550