MySQL query wrong :(

gistfile1.txt

$query = "SELECT * FROM `users` WHERE sid64 = :sid64";
  $query_params = array(
		':sid64' => $sid64
		);
	try {
		$stmt = $db->prepare($query);
		$result = $stmt->execute($query_params);
	} catch (PDOException $ex) {
		return ("Conversion Failed!");
	}