Shortcut to evaluate an expression on the REPL in Cursive Clojure?

Open File --> Settings --> Keymap

Click on the "Collapse all" to be able to find the options easily

Then go to Main Menu --> Tools --> REPL

You will have there all the actions for the REPL. The specific one that you are asking for is "Run top form in REPL"

According to the official site:

Key bindings

Currently Cursive is distributed without any shortcuts assigned to its actions - it’s too difficult to avoid conflicts with existing actions on all platforms. We’ll be suggesting some possible keybindings for various features of Cursive as we discuss them. When we talk about Mac keybindings we refer to the Mac OS X 10.5+ keymap, which is what we use - not the old Mac OS X one.

Assign your shortcuts yourself, here is how. See section keymaps.