I’m not even sure there’s one for solving your easy CVX models. For instance, there is no NEOS capability for CVX, although there is for some solvers used by CVX.
However, you can look at Installing CVX on MATLAB Online , which links to https://www.mathworks.com/matlabcentral/answers/501309-installing-cvx-on-matlab-online . I have no first-hand knowledge whether that actually works.