SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8bea5bbe0630d08a58ac5743cb4fee32cb6e440a9e004e3d33120c897eaddf6' 
  AND token = 'lz7Fc+dl0hLbLVsvz0g7SsPLn4ZM9Cy7dKOHmls8BQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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