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 (
    83475, 83482, 83483, 89742, 89743, 83448, 
    83453, 85277, 85335, 85336, 84516, 
    84582, 85324, 85421, 85472, 85523, 
    89760, 89761, 84512, 84578, 85048, 
    85049, 85134, 85135, 85180, 85181, 
    85226, 85227, 85044, 83062, 83615, 
    90898, 90977, 89811, 89863, 89935, 
    91501, 83017, 83568, 90850, 90929, 
    91069, 89744, 89745, 85370, 84626, 
    89039, 85299
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00113

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "25.94"
    },
    "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": "21.14",
        "eval_cost": "4.80",
        "prefix_cost": "25.94",
        "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 (83475,83482,83483,89742,89743,83448,83453,85277,85335,85336,84516,84582,85324,85421,85472,85523,89760,89761,84512,84578,85048,85049,85134,85135,85180,85181,85226,85227,85044,83062,83615,90898,90977,89811,89863,89935,91501,83017,83568,90850,90929,91069,89744,89745,85370,84626,89039,85299)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}