I shal assume that you have redeemed a pre-order beta code.
The following is from the Beta FAQ and is currently all the information we have regarding the Email with the Beta Token.
9. When will I get my Private Beta token?
Tokens will be sent close to the beginning of your Beta start date. For PlayStation 4, before August 25 at 10 AM PT. For Xbox One, before September 1 at 10 AM PT.
The Beta tokens will be sent through to the registered email address that you have provided in your Call of Duty account
Additionally, Tokens will be viewable via your own Beta status page --> https://profile.callofduty.com/promotions/redeem/cod/beta
25 digit Xbox Beta Tokens will then be entered via Xbox.
All the best
When i go to the status page it doesnt list a token, it says you have already redeemed a beta code. When will it be emailed / provided?