The warrant is for public intoxication in California. I’m planning to go to Mexico.
It is highly doubtful that you would be detained. BUT, it depends on the severity level of the offense in CA. It is likely that public intoxication is a misdemeanor or petty offense in CA. Typically, misdemeanors/petty offenses are non-extraditable offenses. Meaning, if they detain you in another state, say MN, that the authorities will not extradite you to CA to take care of the warrant.
By far, the best course of action is to take care of the warrant yourself by contacting an attorney licensed in CA or going to CA yourself to handle the situation.