SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad74a24a7433d858323aa4d34f982ddde55b8f872b979f63fa55bd9bf0a15022' 
  AND token = 'qPJVvVHcvLna8qTb7orgmhvXHwHqCNtXg7NBDglvPGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}