I actually like making packed lunch. It is the one part in the day I feel smug competent. It's all downhill from 8am...
Buy one of those lunchboxes with containers. DD's has one large and two smaller sections.
I usually give her a sandwich - eg houmous, ham, cheese, cream cheese and marmite. She also likes rice cakes or ryvita.
Then in one of the smaller sections, two types of veg chopped up - eg cucumber, cherry tomato, carrot, celery, pepper.
In the other section, two types of fruit - eg sliced apple, satsuma, raisins, grapes, blueberries (try to think of things that won't go too squishy/slimy through the day).
She seems very happy with this, every day is slightly different for her, but it is always easy for me. Once you get used to it, it probably takes 1 minute to make.