In a large pot of boiling salted water, cook pasta, stirring occasionally, until al dente. Drain and immediately rinse pasta with cold water. Drain again and transfer to a large bowl. Drizzle with oil to prevent sticking.
Meanwhile, in a small bowl, whisk mayonnaise, lemon juice, and granulated sugar until emulsified; season with salt and pepper.
Add tomatoes, celery, carrot, and olives to bowl with pasta. Pour dressing over and toss until well combined, about 1 minute.
