What's nice about those class is you have the source, in C:\Program Files (x86)\Windows Kits\10\Include\10.0.18362.0\winrt\wrl\client.h (adapt to your context and Visual Studio version):

template <typename T>
class ComPtr
{
public:
    typedef T InterfaceType;

    ...

    // query for U interface
    template<typename U>
    HRESULT As(_Inout_ Details::ComPtrRef<ComPtr<U>> p) const throw()
    {
        return ptr_->QueryInterface(__uuidof(U), p);
    }

    // query for U interface
    template<typename U>
    HRESULT As(_Out_ ComPtr<U>* p) const throw()
    {
        return ptr_->QueryInterface(__uuidof(U), reinterpret_cast<void**>(p->ReleaseAndGetAddressOf()));
    }

    // query for riid interface and return as IUnknown
    HRESULT AsIID(REFIID riid, _Out_ ComPtr<IUnknown>* p) const throw()
    {
        return ptr_->QueryInterface(riid, reinterpret_cast<void**>(p->ReleaseAndGetAddressOf()));
    }

    ...
};

So, yes, As basically calls QueryInterface underneath.