The "locked in" time would be a contingency period, you typically have 5-17 days to do an inspection (due diligence period) to get the title info, disclosures, inspection (any inspection done), and then release that contingency.

Contracts also contain other contingencies that can protect the buyer and seller from having the property tied up for too long.

There are like one billion contingencies inside that question.

Your offer should include a financing and appraisal contingency, so if the property doesn't appraise your EMD will be refunded.

This is still considered some contingency because if you dont get the HML then you're still back out so the financing contingency remains.

Sometimes the seller requires quick closings, no contingencies, as-is offers.  

Waive the contingencies you feel comfortable with, move up closing dates, have lenders engage with agents, show proof of funds right away, and show your ability to purchase the property.

Then make the offer and lose to the cash buyer with no contingencies and rinse and repeat until the market shifts or you score a great buy. 

Make the deal contingent upon the property being delivered vacant (this would require the Seller to agree to serve them a "Notice to Vacate")2.

If someone lived in an old house or in a bad neighborhood, I could see enticing them to sell to you, and getting in to contingency on a new buy.