Snails do have brains but the brain that snails have is different from the brain that humans have.
Snails have a group of brains in different areas of their bodies and do not have spinal cords like humans do.
The snail has a set of ganglia (groupings of neurons) that distribute the control of the various parts of the snails and snails also have 2 cerebral ganglia supplying the eyes, tentacles and head.
So yes snails to have brains but they are different from human brains and other animals brains and it's different in the way the brain controls the snails motions and keeps them alive.
So amazingly snails have more than one brain that controls their body instead of one big brain like humans have.