Regardless of the use or non-use of the death penalty in California, Phil Spector will not be executed because he was not found guilty of first-degree murder. He was found guilty of second-degree murder, the distinction being that the former crime is eligible for the death penalty while the latter is not.
He has not yet been sentenced, but the "standard" sentence for second-degree murder is 25 years to life in prison. Since he will be 70 on his next birthday, a sentence of the minimum, 25 years, will amount to life in prison as far as he is concerned, even if they knock off a few years for good behavior.
He is not in good health to begin with, and prison health care is not very good in general. Incarceration will probably shorten his life; he is a borderline diabetic, and prison fare is not known for its healthful qualities.