SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '041389f3e378911bb01d57a5885e47c203f9cd2d4f652927d59df575ddb10b89' 
  AND token = 'tlz5pEHQs0/89lO+HrrVPusIoWCqiesWlHtZ6DjboJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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