from time import datetime

date_start = datetime(year_start, month_start, day_start)
date_end = datetime(year_end, month_end, day_end)

# df is your pandas dataframe
sel = df[(df['timestamp'] >= date_start) &\
         (df['timestamp'] <= date_end)]

# tested with
# python 3.9.4
# pandas 1.3.2