The earlier you leave, the easier the commute. You could get there in an hour or under if you leave from TO 6:30 or 7:00 AM. At 7:30, the roads are getting busier, and you could be looking at 1 1/2 hours.
The trip back from Century City at 6 or 6:30 PM will be long, can easily be 1 1/2 hours.
You might look for alternate routes, like taking Topanga Canyon to PCH, and then taking Sunset into Century City.