I think the music you're looking for is "Shufflepuck Cafe". The music from the this game was included on side B of the Commodore 64's Tool Box Introductory Audio Tape as an example of the Amiga's musical capabilities. I should imagine the music demo was probably the same on the Amiga tape.
Download the Shufflepuck Cafe game by Domark (1989), fire up your Amiga emulator of choice and see if that's the music you mean.
