Urine test : protein (1+), trace of blood, few bacteria, hyaline cast/lpf (0-1), mucus rare. RBC/hpf 3-4, WBC/hpf 4-6, should I be worried?

No. Even if this is not a contaminated sample, if you have no symptoms you are close enough to the reference range to consider yourself healthy.
How do you feel? The urine test contains some abnormal findings but does not show a typical picture of urinary tract infection. How you feel is more important. Try to increase fluid intake. If you experience fever, burning sensation, low back pain, low abdominal pain, urinary frequency and urgency, you may need antibiotic treatment. A urine culture would be helpful.