That concrete screw will come out. I anchored a bag like that and it held for a while, then pulled loose and I ended up getting cut pretty good on my left arm when it wrapped around and hit me.
I used an o-ring with a wood screw tip at the top. On the bottom I used a sheet of 1 inch plywood cot to a 2 foot by 2 foot square. In the middle I used another o-ring, this one with a nut and bolt attachment. To hold it down, they sell sand bags for this purpose; I'd get 2 50 pounders. Or you can use weights from a weight bar set. Again, 100 pounds should hold it down.