There will be 4 KLM flights departing for AMS between your arrival at T4 and your scheduled departure.
KLM only officially offers all-day baggage drop off at AMS; their
website instead suggests that in Europe, bag drop commences "at least 2 hours prior" to departure.
I'm not sure how willing they would be to take your bag so early at LHR; the fact that you're in business may help.
But why are you not seeking to change your ticket to an earlier flight?