The old telephone switchboard jack is a strong contender for "first" in this race. According to the linked Wikipedia page, manual switchboards (which featured operators plunging ~2-inch long pointy-ended jacks into sockets over and over as they connected each call) were in widespread use by around 1880, so they predate RoboCop (1987) and Neuromancer (1984) by about a century.
The 3.5mm stereo audio jack, being a single exposed cylinder with a dramatically tapered end, presents a much more 'spike'-like appearance than coaxial connectors with their center pin partially concealed in a collar, and also predates the Radio Corporation of America's introduction of the coaxial RCA connector (1930s) by several decades.
Given that this very same 1/4-inch jack is still in widespread use for musical instrument, microphone, and audio patch-cord applications, it's safe to assume that they are a familiar sight to anyone who has spent time around film sets or recording/production studios, which presumably includes the writers and directors of movies and TV shows. So in addition to the fact that this connector significantly predates the contenders mentioned in other answers, its ubiquity also lends weight to the idea that it likely inspired various fictional 'data spike' connectors.
