SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fc80776cf63264e864622c3f09c8e33d60d16fc56a521ea65e0090c2f9b052b' 
  AND token = 'uJNbbO+t7lxohvQDjMQjdKx76FQdzWemBtIxK2bj5YA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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