Here's my data point regarding Lexus timing belts. This belt was the original from my LS400. I took this photo in November 2021 (more for the timing mark location than the belt condition). The belt had 90,216 miles. Toyota recommends timing belt change every 72 months or 90k miles, whichever occurs first.
While it was at the mileage limit, 23 years = 276 months. 204 months delinquent.
The face of the belt looked like this. The toothed side looked fine. Would I do this again? Probably not.
View attachment 248132
Your belt will probably be OK for the trip. You're right at the mileage limit. How old is the belt (I'm assuming the present belt is original)?
Do you have the maintenance schedule for your RX?
The face of your belt looks OK; I would try to get a look at the toothed side.