Do you prefer typing emoji instead of stopping to choose them from a picker?
You can do this when writing a post on Mastodon's web interface by typing a : (colon) and then a keyword without a space. This will automatically bring up emoji with that keyword in their description.
For example if you type :sun it will show you emoji with the keyword "sun".
(Note that if there are many matches for a keyword, you may need to go to the picker to see them all.)