I think this is fairly easy to achieve for this inner list. The values seem to be all zero's so...
jq '.' < yourjsonfile
Just to provide another approach. When working with lists, dicts and other types python is the right tool. To give you an idea on how you could retrieve the values from the list you'd do something lik:
mylist = [[1645128660000,0],[1645128720000,0],[1645128780000,0],[1645128840000,0],[1645128900000,0],[1645128960000,0],[1645129020000,0],[1645129080000,0],[1645129140000,0],[1645129200000,0]]
for k,v in mylist:
Or using list comprehension
[v for k,v in mylist]
should be sufficient. There is also this awesome page where you can play around with jq: https://jqplay.org/#