Cantera 2.5 and Python 3.7 seem like they are supposed to be compatible with .cti files, but starting in Cantera 2.5 .cti files are obsolete. The best solution I found is to convert .cti files to .yaml files, the new recommended chemistry file format. At least on my system, all of these functions perform well on .yaml files. You can test this with the files that come with the Cantera installation (Program Files/Cantera/data for the standard installation).
To complicate things further, Cantera's MATLAB toolbox does not include the cti2yaml function (or apparently the ck2yaml function). My solution was to find the Python function cti2yaml.py (installed with Cantera) and use Python to create the desired .yaml file. Now all those MATLAB functions run quickly on the .yaml file with no hangs. For converting Chemkin files, the MATLAB toolbox has ck2cti.m, then the process above can convert cti to yaml.
This is mostly a Cantera problem, but it seems unique to running Cantera in MATLAB.