No, a light year is not a measure of time, but of distance.
It's the distance light travels in one year at 186,000 miles per second.
How many seconds are in a year?
Do that calculation, then multiply the result by 186,000.
The result is the distance light travels in one year.
Then figure what the distance would be for 320 million of them.
There are some things we are just not designed to truly comprehend.
Quantum Mechanics theorists say mathematically, there is no such thing as time. Time does not exist. There is space time but not time by itself.