Two things IMO
make sand "live". One is the nitrifying bacteria that is on it that establishes the nitrogen cycle. Two is the fauna that is established in it. The microscopic to critter size (for lack of a better word) organisms that live in the sand. As long as your sand has been wet and in a tank with livestock then I would suggest your substrate would be OK. If the sand dried out or there was nothing in the tank to produce ammonia to feed the nitrifying bacteria then it might not be alive. My guess is that you are OK.