Static method in Volt - there's no support for it in Phalcon 3.0.x still.
This is the most confortable solution to the problem:
$voltCompiler->addFunction('myVoltFunction', function () {
return __NAMESPACE__ . '\\' . 'AnotherClass::getMyRealStaticMethod()';
}
);
Volt usage as regular: {{ myVoltFunction() }}