We report on a search for continuous gravitational waves (GWs) from NS 1987A, the neutron star born in SN 1987A. The search covered a frequency band of 75-275Hz, included a wide range of spin-down parameters for the first time, and coherently integrated 12.8days of LIGO data below 125Hz and 8.7days of LIGO data above 125Hz from the second Advanced LIGO-Virgo observing run. We found no astrophysical signal. We set upper limits on GW emission as tight as an intrinsic strain of2x10-25 at 90% confidence. The large spin-down parameter space makes this search the first astrophysically consistent one for continuous GWs from NS1987A. Our upper limits are the first consistent ones to beat an analog of the spin-down limit based on the age of the neutron star and hence are the first GW observations to put new constraints on NS1987A.