As soon as I made the purchase I got access to the code - I redeemed it right away without any problems whatsoever.
CDKeys was also the cheapest place offering this at the moment, I sometimes buy the keys wholesale and even there it was more expensive than here, so absolutely cracking price. Saved about 50% over the console version.
CDKeys is always reliable, and they don't have silly steps like some other companies who ask for phone or even photo verification - None of that nonsense with CDKeys.com, you just place the order and get yours keys.
Never had a problem so far and I've bought both Xbox One and PC codes from here.