SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c7c2c086f5c9a6290b6c3a797f10bc4c46a7ed7c8e81d527cd83431bff7058b2' 
  AND token = 'wamkyrSttAAyctYR6QReRD2eVN8If8nMKy1nU7Ynqk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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