lock in

verb

Used other than figuratively or idiomatically: To secure (someone or something) in a locked enclosure.
“The dog won't escape now we've locked him in.”
“The dog won't escape now we've locked him in the kitchen.”
To fix the value of (something potentially variable).
“I've locked in a rate of 5%.”
“I've got a 5% rate locked in.”
To prevent (someone or something) from escaping, deteriorating, or switching to an alternative.
“Our new foil packets keep the flavour of the crisps locked in.”
“Companies find various ways to try to lock in a customer base by preventing the products or services from being fully fungible.”
To synchronize (especially a rhythm section) into a groove.
To focus entirely (on something).
“I need to lock in for this exam I'm taking tomorrow.”
“The missile's path is now locked in.”