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 (
    85950, 85951, 85948, 85909, 84692, 85910, 
    85911, 84957, 85906, 85907, 84852, 
    84751, 87975, 85908, 84753, 84860, 
    84863, 92922, 92923, 92924, 92925, 
    92926, 92927, 92928, 92929, 92930, 
    92931, 92932, 92933
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00069

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.07"
    },
    "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": 29,
      "rows_produced_per_join": 29,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.17",
        "eval_cost": "2.90",
        "prefix_cost": "13.07",
        "data_read_per_join": "110K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (85950,85951,85948,85909,84692,85910,85911,84957,85906,85907,84852,84751,87975,85908,84753,84860,84863,92922,92923,92924,92925,92926,92927,92928,92929,92930,92931,92932,92933)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}