Since I could only view the magazine's cover, a search was done at copyright.gov for any possible renewals for "Now" in the year 1954 (original application). There were no renewals for this magazine, so there's no evidence copyright continues to be claimed on it.
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.