exists with this exact title. The phrase is most likely a search term for: a) An adult / porn parody (e.g., parodying Wife Swap with a key party twist). b) A fictional concept discussed on forums or in pitch documents. c) A retro-themed party event organized by lifestyle organizations (e.g., “Key Party & Wife Swap Night” as a private social).
The concept has been a recurring theme in film and television, used to explore the complexities of human relationships: Swingers Wife Swap 2 - The Key Party