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 (
    85739, 85749, 85759, 88984, 88193, 88205, 
    88234, 88238, 90837, 89843, 89895, 
    89968, 91534, 85733, 88980, 88997, 
    88662, 88709, 84700, 85670, 85690, 
    85702, 85714, 88495, 88961, 91437, 
    91451, 85719, 88717, 85800, 88755, 
    88756, 85678, 87506, 87517, 87522, 
    87533, 88453, 88470, 88486, 88567, 
    89837, 89889, 89961, 91527, 88522, 
    88568, 88957
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00108

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 (85739,85749,85759,88984,88193,88205,88234,88238,90837,89843,89895,89968,91534,85733,88980,88997,88662,88709,84700,85670,85690,85702,85714,88495,88961,91437,91451,85719,88717,85800,88755,88756,85678,87506,87517,87522,87533,88453,88470,88486,88567,89837,89889,89961,91527,88522,88568,88957)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}