Call me crazy but maybe it was just a test if Iran have those missiles they claim they have.

Iran claims to have operational hypersonic missiles (Fattah-1, Khorramshahr-4) capable of Mach 15.

https://nationalsecurityjournal.org/irans-hypersonic-missiles-summed-up-in-4-words/

This is 18376 km / h flying on < 100km orbit. You need some kind of radar mesh to detect that but even if you have one there is probably 1 minute left for reaction. Only skynet level defense can do it.