Before the bottle is opened, it will last indefinitely. Keep it stored upright, but tip it over once a year so the cork gets a touch of wetness. If you're planning on storing it for many years, you should seal the top better by dipping it in wax. (This is specific to Woodford, which is capped with a cork and wood, which are breathable. Some whiskies already have a wax seal.)
After the bottle is opened, it will still last indefinitely until the bottle is roughly a third emptied. Until that point enough spirit evaporates into the empty air that the environment is right. But once you've had more than a third or so of the bottle, the air/whiskey balance can throw off the spirit and you may see it turn cloudy and the flavor will go off.
Here's the good news- this won't happen for about two years, so you've got plenty of time to finish that bottle.