California has "ban the box" and as a practical matter:
1. most "boxes" on employment application ask about Felonies not misdemeanors.
2. I'm not an expert but the few times i've looked into it "criminal background check" is nowhere near as comprehensive as people think. it involves going to each county where you think the person resided and looking up records there. so according to you even if they thought to look in the county where your record is, they wouldn't find anything.
https://www.shouselaw.com/california-ban-the-box-laws
California law still prohibits employers from asking about, or considering, criminal convictions that have been expunged. AB 1008 takes the law a step further. It bars employers from considering any criminal conviction, expunged or not, prior to making a conditional job offer. The law applies to both felony charges and misdemeanor charges in California.