Orchestral string players often have mutes that are clipped onto the strings behind the bridge, so they are quick to apply and remove, and don't get lost. One type has a small "handle" to make it easier to apply quickly.

It's not an instantaneous operation, but 5 seconds should be enough time for a professional standard player. With the easiest type to operate, you can do it one-handed while still holding the bow, and with the violin still under your chin.

Orchestral string players often have mutes that are clipped onto the strings behind the bridge, so they are quick to apply and remove, and don't get lost. One type has a small "handle" to make it easier to apply quickly. Another type just pushes against the face of the bridge, instead of being clipped on top of it (which is a bit more fiddly to do).

It's not an instantaneous operation, but 5 seconds should be enough time for a professional standard player.

This video doesn't really show a "quick change," but it gives a some idea of what is involved - not much, after a bit of practise.