You can pause a plug by visiting your Plugs page. The Plugs page is accessible by the main left-side menu or by visiting directly this URL , (logged-in users).
In the Plugs table, find the plug that you wish to Pause and click the green "ACTIVE" button in its corresponding row and wait for the system to update. Once successful the status of the your plug will be updated to "Paused" and your check out cart will inaccessible for this plug.
You can similarly activate a plug by clicking the "PAUSED" button in its corresponding row.