Saute carrots, celery, and onion in oil and butter until tender, about 3 minutes. Add garlic; cook 1 minute longer.
Stir in the chicken stock, tomatoes, kidney beans, chickpeas, zucchini, thyme, and oregano, and season with salt and pepper.
Bring to a simmer and cook for 20 minutes.
Ladle into bowls and drizzle with a little olive oil (optional).