Qatar has never been allied with Iran. It has had economic partnerships, especially around the oil fields that Israel blew up, but that is not an alliance. Iran does not have military bases in Qatar.
Why would Iran need a base in Qatar? It's right next door.
Iran and Qatar do (did?) have military cooperation agreements, not only economic. [1] That's not a NATO style treaty but Qatar doesn't have a NATO style treaty with the US either.
