This looks very suspicious. Found a reddit thread and did some digging. Draken International has a Mirage F1M plane that looks to be able to fire such a missile. Possibly at the airport the missile was found at? Supposedly recently purchased from Jordan. Wiki for that type of missile seems to check out too. Wft is going on?

http://www.drakenintl.com/catalog/aircraft-inventory

https://www.reddit.com/r/news/comments/icj9bw/live_french_airtoair_missile_found_in_florida_is/g23oibd/

https://en.wikipedia.org/wiki/Super_530

Digging help appreciated, non-US anon here, this is not really my field.