Heat olive oil in a large skillet over medium-high heat. Add turkey and onion; cook, breaking up the turkey, until the turkey is cooked through and the onion is soft and translucent. Add garlic and cook just until fragrant, about 30 seconds. Stir in flour and stir to coat the turkey and vegetables. Add ketchup, chicken broth, salt, and pepper. Bring to a boil; lower heat and cook until thickened. Stir in frozen peas and carrots.