According to Yahoo! Maps, it take about 35 minutes from Alhambra to LAX.
I would assume that you will take I-10, I-110, and I-105.
It's now 1:57pm and according to Sigalert, there is no traffic on those freeways.
I, however, would leave Monterey Park/Alhambra/Rosemead at 1:30 just in case.
here a idea might even save tyou some money and time
drive to he Union station (parked at the metro building)(on vingnes)
then for $7.00 you can take the flyaway to lax.
and i think the parking is about $6.00
now what time is your flight?