Python makes it pretty trivial to load compiled modules as third-party packages, and given the core language itself is already implemented in a similar way, at least for CPython, creating numerical packages as thin wrappers around pre-existing BLAS implementations was probably easier in Python than in Lisp.
It might seem stupid, but operator overloading and metaprogramming features make it fairly simple to emulate the syntax of other languages scientific users would have already been familiar with. Specifically, NumPy, SciPy, and matplotlib quite obviously tried to look almost exactly like MATLAB, and later pandas very closely emulated R. It's a lot easier to target users coming out of university programs in statistics and applied math who have been using R and MATLAB and teach them equivalent Python libraries. Trying to teach people who aren't primarily programmers to use Lisp is going to have a much steeper learning curve.
It really didn't explode in the 2010s, either. You're thinking of Facebook with pytorch and Google with TensorFlow making it dominant in deep learning, but the core scientific computing stack goes back way further than that. As for why Google and Facebook chose Python rather than Lisp, I think it was just already one of their officially supported languages they allowed internal product teams to use. Lisp was not. Maybe that's a mistake, maybe it isn't, but it's a decision both companies made before they even got into deep learning.