On centos7, the default node is too old. However there is a node12 package that is shipped but node executable is not in the default PATH.
LocalSettings should be adjusted to:
$GLOBALS['wgMathoidCli'] = [
'/opt/rh/rh-nodejs12/root/usr/bin/node',
'/opt/mediawiki/mathoid/cli.js',
'-c',
'/opt/mediawiki/mathoid/config.yaml'
];