public function deleteAccessToken(AccessToken $accessToken)
{
$stmt = $this->db->prepare(sprintf('DELETE FROM %s WHERE client_config_id = :client_config_id AND user_id = :user_id AND access_token = :access_token', $this->prefix . 'access_tokens'));
$stmt->bindValue(':client_config_id', $accessToken->getClientConfigId(), PDO::PARAM_STR);
$stmt->bindValue(':user_id', $accessToken->getUserId(), PDO::PARAM_STR);
$stmt->bindValue(':access_token', $accessToken->getAccessToken(), PDO::PARAM_STR);
$stmt->execute();
return 1 === $stmt->rowCount();
}