yes, you can find coffee bean models easily. Probably any of the stores selling 3d models will have them. Consider buying something like that where it happens to come with something else you need. Doesn't make sense to buy a single coffee bean for $12 if you can get a coffee machine, cups, mugs, bagel, plates, etc all in one scene for $20. Unless, it's a Damn good coffee bean.
For the counter top, you can probably manage that material with the procedural textures. Definitely try out some of the premade materials, and check the cloud library if you're a beginner.
If you go with textures you'll need the image, tileable if it needs to be repeated, but for a scene like that it might not be necessary, and you'll need to create/obtain roughness map, bump map, spec map at least. Those get plugged into the corresponding slots in the generic material. Keep in mind, generic material doesn't use the same scale as other keyshot materials for some reason. So a roughness of .2 in generic is not nearly as rough as a roughness of .2 in other keyshot materials.
The wall? No reason to render that as an object really. You can just use it as a backplate. You can always change that later in photoshop, but NOT if you have transparent objects. There are some tricks to getting transparent objects to actually have transparent alpha, but keyshot does not have that as an option. So the trick is basically figure out a way to render an alpha mask for the refractions.