Of course there is the normal key pressed opcode, which you can use if you just want to check if some action is performed by pressing a key:
| CODE |
| 00E1: player 0 pressed_key 19 |
There is also a cleo opcode, to figure out what specific key is pressed:
| CODE |
| 0AB0: key_pressed 0x73 |
In the help files (Cleo 3 Code Library), you can find a list of virtual key codes.
I don't know exactly what you want to make, so if you mean something else, please say it.