Question about "You have 1 day left before your inactivity causes your LP to decay"

Does the timer start counting down from hours on the last day? Because 1 day left could mean 47 hours or 1 hour. (if that's how it works) I wish Riot would incorporate a days/hours/seconds countdown for Ranked decay like they do for special events.

I want to play Nexus Blitz but I'm scared that after one of my games, I'll suddenly be Gold again. So should I play a Ranked game ASAP to be safe?