The "Karaoke Crown Passport" were passes made by Luna that allowed the Inner Sailor Guardians entry into the Karaoke Crown. These items only existed in Pretty Guardian Sailor Moon.
The passes allowed the girls to get into the Secret Base formed inside the Karaoke Crown. Each pass had a picture of Luna's head on it including a planetary symbol of the Inner Sailor Guardians for the Sailor Guardians who owned the pass.