SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81e48303f57e620db1b2e73143b68a159d62210615ccc5a634024e541b2b5c63' 
  AND token = 'AvOZboN6Zv+OrmRjUQB/rhnQjpwelRx6SZn/NCafGxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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