Solution:
Try adding the following lines in wp-config.php file:
define('WP_HOME','http://example.com');
define('WP_SITEURL','http://example.com');
Just replace values with the URL of your new domain.
If that doesn’t work, check this tutorial on other different ways to fix this issue, among them a detailed step by step guide on how to modify those values in a database (solution already mentioned by Ingo Seidel answer).