How can I find art about XY?

Go to a library. Ask a librarian. They may not be able to give some magic bullet answer (a fantasy anyway), but they can point you in the right direction to answer these kinds of questions for yourself.

But I suggest you narrow your focus. You might want to start out looking for topics a little less broad and vague as "time" and "joy". That would be like trying to research 20th century music that incorporated drums or guitars.

I tried "art with the theme of joy" in an Ecosia search and got a variety of results that looked decent. A search like that should be a good starting point. Take note of the artists that have used that theme and see what else they do. You could follow up by searching for books about what you find. Also, look on art gallery websites etc for what exhibitions are or have been that may cover your theme.

Do you have a local art group (even for people who get together to make art) and ask them?

Try looking up an Album of paintings e.g. Printed in North Korea

if you want to experience art including an element of time, try "music". beware, it's addictive :D