The fastest way to reindex your Magento data is to do this manually via SSH.

To reindex the Magento data manually, you need to have an SSH access to your web hosting account. All SiteGround hosting accounts come with SSH access, so if you are a SiteGround customer, you can order your SSH from your SiteGround Customer Area -> Order Tab.

All you need to do to reindex your Magento data manually is to log in your hosting account via SSH, go to your Magento installation directory (e.g. public_html/store) and execute the following command:

/usr/local/bin/php shell/indexer.php reindexall

This command will reindex data by all indexers.