To determine the index of refraction of a material for a given wavelength of light, we need to know the dispersion characteristics of that material. The index of refraction varies with wavelength for most materials, and the value for red light at 450 nm will depend on the specific material in question.
If you provide the material for which you would like to know the index of refraction at 450 nm, I can provide you with a more accurate answer. Different materials have different indices of refraction, and the index for red light at 450 nm can vary from material to material.