Rule 111.12 · Tokens

If an effect instructs a player to create a token that is a copy of a nonexistent object, no token is created (see rule 707, “Copying Objects”). This does not apply to an effect that would use the last known information of an object.

Example: Mimic Vat has a triggered ability whose effect gives you the option to exile a card and an activated ability that says “Create a token that’s a copy of a card exiled with this artifact. It gains haste. Exile it at the beginning of the next end step.” If no card has been exiled with Mimic Vat’s triggered ability, no token is created.