What is a quick server search? The last time I looked at the Xonotic server window there was a method to highlight your favourites (or bookmark the IP). You could also type the name of the server in the search thing at the top and the game would filter the servers for you.
Example: run Xonotic, go to the multi-player menu window and enter Simba in the search box. There should be only one server listed "Simba CTF". You may need to have a play with the full/empty buttons to show the full server list.
Alternatively if you use a good quality OS you maybe able to use XQF to store your favourite server and launch Xonotic.
In case your server list is empty, you can find Simba CTF with "connect 87.250.139.171:26000"
Yours
Space_Man