You could store your execution times in an environment variable.
Before this script will work, you must create the LastExecutionTimes environment variable.
$maxTime = 60
$maxCount = 3
$now = Get-Date
# Get execution times within the time limit.
$times = @($env:LastExecutionTimes -split ';'|
Where-Object {$_ -and $now.AddSeconds(-1 * $maxTime) -lt $_})
$times += '{0:yyyy-MM-dd HH:mm:ss}' -f $now
$env:LastExecutionTimes = $times -join ';'
if($times.Length -lt $maxCount) {return}
# Reset the execution times
$env:LastExecutionTimes =''
Write-Host 'Continue Script' -ForegroundColor Yellow