SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '542550184e9074d25a97b5630b5d9c60939662024527d65a00158cc255ff3844' 
  AND token = 'joCW8PcPp0bwUuZ4PTXoMkID7TTihuwg4XBgIqoZo/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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