@{$key_hash{$key}{$oid}[0]} is an array. You can tell that by the '@' on the left. You're close, those. You just need to go one more level deep.

$key_hash->{$key}{$oid}[0][1] will do you just nicely.

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We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.