Exact search via api not working

 I am trying to run below code to search the file in this box, I am using OAuth2 JWT authentication method, authentication works fine, but the search doesn't give any output, please suggest.

snb_regex_string = "INB-DEV_url_hit.png"      <=== Filename
results = client_box_app.search().query(snb_regex_string, result_type='file',
content_types='name')
for r in results:
print(r)