SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b0d3975c8917f35b986bbbb7f2c11dca6dfc33cef4bd78cbf9934d535f4714c' 
  AND token = 'cNZfiEG3syzPAhZbWXgqpkLRol8KUF9Gj/LSaD9JQGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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