Does AppleCare+ provide free physical cleaning service for MacBook?

Not officially; the plan covers hardware failures and software problems. If it was in for a repair, they may clean it if it is causing a problem.

Hi,

I think they don't offer such service, though if your MacBook Pro has trouble by the dust, they would.

I don't believe so. However, when I've brought in my Mac for servicing I noticed that it was cleaned, although not necessarily inside.