1. make sure the values changed in database
If you can't login to wp-admin > settings to confirm that, you can go to database, wp_options table and look for siteurl and home values
2. add code to wp-config.php
Add these lines to wp-config.php
define('WP_HOME','http://example.com');
define('WP_SITEURL','http://example.com');
3. Clear your cache
Make sure that you clear the cache from any cache plugins you're using and also from your browser
Also try adding this to wp-config.php (note "false")
define( 'WP_CACHE', false );
4. check https / ssl related plugins
You might be using any plugin which is causing this, like ssl insecure content fixer, etc.
5. Cloudflare or other dns side redirect
Make sure that the site isn't using any dns based redirect
6. disable all plugins and confirm
7. change theme to default and check