You can certainly use a Smart Album to find all the pictures with a specific keyword.

The "TrafalgarSquare" field here is a pulldown menu with a list of all keywords. Or you can type the first letter or two and get down the alphabetical list. You can see that I have 27 keywords like this. Unfortunately, I seem to also have the keyword "Trafalgar Square" (with a space,) so I set up a Smart Album with

to find those. Luckily, there's only one, and I can quickly change it.
Now there are no "Trafalgar Square" pictures, so I can go to keyword manager (⌘K) and with Edit I can find that and hit delete.
If there had been 20 of them, I might just add the right Keyword (so they have both) and go to Keyword manager and delete the space one-- it would say there are 20--are you sure?
If you don't use keyword shortcuts, quickpicks, and filters, be sure to try that-- it's a great time saver.
You can use keywords to make lots of things easier. For picking Favorites, see this:
Choosing Favorites using Keywords in Mac … - Apple Community
Keywords Smart Albums are among the most powerful tools in Photos.