All depends on how long the videos are.
For packs/cash the vids are normally between 15 and 30 seconds long. I'd estimate on a good day you could probably get around 80 videos to credit, so a little over 40 mins would be a good barometer - however you have to go back several times a day and on multiple devices (I swap between the laptop, my huddle and my Ipad and Iphone), so its never in a long period.
For Tokens, again it depends on how long the videos are. Recently the video has been around 4 mins and you have to watch 3 to get 1 Token, so its around 12 mins per token. Last week however there was a video that was 30 seconds - watch that 3 times for a Tokens and its 1 and a half mins per Token.
There is a limit to 50 Tokens you can farm in one day - and most of the time the "window" to farm seems to be closed, so its a case of working out when it resets and doing it then. For me in the UK, I notice it resets at 1AM in the morning each day. Thankfully I work late, so at 1AM I start watching videos via my phone, reloading the page/videos once watched until I either get locked out, or hit the 50 target.
Last week I managed to hit 50 tokens in a little over 2 hours - which considering I was doing other things at the same time (watching TV, catching up on Facebook etc...) that was pretty good. Last night the 4 min videos meant I earned around 20 tokens before I went to bed just after 4AM. So its all kind of relative in a way.
I normally farm for a week or two, then stop for a week or two, then start again. Last month or so its been hard to watch videos on Facebook as they don't credit, so my packs and cash could and should be healthier than they are currently.
I've not used over 100 Tokens in a season in over a year, as I refuse to buy scouts anymore as I don't think they are worth it. I can earn 100 Tokens in 4/5 "bad" days (or 2 in just good days), so I continually see my Token stacks increasing as a result. Farming for Tokens did disappear for about 2 weeks at the start of last season and I was just about ready to say it was gone for good when it reappeared - so its to be noted that farming isn't guaranteed to work all the time (it has disappeared before for days at a time) - and it could eventually stop for good - which is another reason why I am in no rush to use my piles until I hit the top of my server.
I've focused on generating cash since the cap was removed about 7 weeks ago. Went from having around 1.2B to the 8.4B I have now in that time. I need to really try to grow Green packs for the future, but really I can't be bothered. I'd rather generate more cash or not bother at all at the moment.