Cook the keto macaroni according to the package instructions in a pot of salted water until tender but not mushy, then drain it using a strainer and rinse it under cold water to stop the cooking process and cool it down completely.

Allow the cooked macaroni to sit for a few minutes so any excess water drains off completely, preventing the salad from becoming watery later.

In a medium bowl, combine mayonnaise, sour cream, Dijon mustard, lemon juice, garlic powder, onion powder, salt, and black pepper, stirring well until the dressing becomes smooth and creamy.

Taste the dressing and adjust seasoning if needed, adding more lemon juice for brightness or salt for balance.

In a large mixing bowl, add the cooled macaroni along with the crab meat, diced celery, chopped cucumber, and green onions.

Pour the prepared dressing over the mixture and gently fold everything together using a spoon or spatula, making sure all ingredients are evenly coated without breaking the pasta or crab.

Once mixed, cover the bowl and place it in the refrigerator for at least 30 minutes to allow the flavors to blend and the salad to chill properly.

Before serving, give the salad a gentle stir and adjust seasoning if needed, adding a small amount of mayonnaise if it appears slightly dry after chilling.

Serve cold as a refreshing, creamy, and satisfying keto-friendly dish.