Apparently, salt in water does two things:

• makes it need less energy to raise in temperature (and therefore somewhat faster to reach e.g. 100°C)
• raises the boiling point, so if you add a lot of salt, it might not start turning into a gas / violently bubbling until 105°C.

https://www.livescience.com/56214-does-salt-make-water-boil-faster.html