Token2Shell/MD currently doesn't support searching Address Book entries within the app. However, since Token2Shell/MD stores its Address Book entries as plain XML text files, you can easily search them using Windows File Explorer or any app that can handle text files.
If you're planning on using File Explorer for searching, we recommend changing the Home Folder to more readily accessible location such as your personal Document folder.
You may also want to change "Indexing Options" for Windows to use "Plain Text Filter" for Token2Shell/MD Address Book entry files (*.t2s). When "Plain Text Filter" is selected, File Explorer also checks the content of the files instead of just file names.
Starting from version 10.14.0, you can also directly start a session by double-clicking an Address Book entry file (*.t2s).