SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5211c966d5c169820b8d4f1165643370cb4a3ebc5431ed0c2c09528913e37597' 
  AND token = '33alYeFL4+GXecAbKFgMf2nd43Oz6sAa6YSR/qW94os=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}