SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '90322420dbc9209fb09ffda5d5be0583677c4090b4b134e50a4a37a2573a68d4' 
  AND token = '9Q3Cdknx6goa+b6OBaMLk0lmhT/7mFx58vDPJgnZhGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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