According to the official keyboard short-cut list, no.
However, you do have the opportunity to define your own keyboard shortcuts within SSMS, as is outlined at the top of the page referenced above. Whether or not you'll be able to create a shortcut to do what you want is another matter.
The alternative is to create the table so that the date/time column has a default value of
answered Jul 07 '11 at 12:16 AM