Can velocity be 0 but speed not 0?

Speed and Velocity are two Words that mean the same.

You may mean, "Can Velocity be 0 but acceleration not 0".

Yes, this occurs when a moving object is changing direction (say from moving forwards to moving backwards) or is just about to move or, at that very instant has just come to a halt.

In all these cases, speed /velocity is zero but the body is accelerating.

Don't forget, the Word acceleration is also used when an object is decelerating (slowing down).