The database credentials of the staging site can be found from the wp-config.php file of the staging site. You can use FTP clients like FileZilla and use the SFTP credentials to access the wp-config.php file of the staging site.
SFTP credentials are available in the staging site details of the Malcare dashboard.
If you just want to access the database, you can also click on PHPmyAdmin button to access it on staging site details page.
Check out this screenshot:
