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 (
    87354, 87352, 87353, 87378, 87376, 87377, 
    87374, 82509, 87373, 82508, 82537, 
    82547, 91482, 82532, 82545, 82546, 
    89571, 82544, 89569, 92584, 92585, 
    92586, 92590, 92591, 92592, 93951, 
    93952, 93953, 93954, 93955
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (87354,87352,87353,87378,87376,87377,87374,82509,87373,82508,82537,82547,91482,82532,82545,82546,89571,82544,89569,92584,92585,92586,92590,92591,92592,93951,93952,93953,93954,93955)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}