If you are equating 'hedonism' and 'living in the moment' then we have a language issue. Which is understandable as our language for such concepts and our language for mental states in general is not very well defined. My interpretation of hedonism is seeking pleasure for pleasures sake. Pleasure is the end goal and the more that is experienced the better!
Living in the moment is a stated goal of many contemplative disciplines including ones that explicitly eschew any hedonistic tendencies by practicing some flavour of asceticism.
Actually an argument could be made that hedonism can lead you astray from the present moment as your yearnings and desires increase for more and more pleasure the more you try and satiate these desires which usually entails some yearning for some pleasure experience in the future.
Living in the moment it seems is closer to the bullseye in terms of ones ability to experience well being. Hedonism just breeds further desire which by definition gives rise to what Buddhists termed Dukkha which is often poorly translated as 'suffering' but a more apt word would be 'dissatisfaction' (1)
