Visit your website using Chrome. Navigate to Chrome menu > More tools > Developer tools > Network, or simply use the shortcut Ctrl+Shift+I to bring it up. The test page may contain many requests, but you can just click your main domain to check the header. You might see X-LiteSpeed-Cache: miss or X-LiteSpeed-Cache: hit. Normally the first visit to a page is a miss, but subsequent visits should be a hit.