SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81dad23fb639c2b83eb475ba2b0c7084ad2ed09ff6e68ec9fd773bebf2f6cb08' 
  AND token = 'wxg4KTRXqHj+vUvyNgpIHMLvzVuYbdBudXCj/8AQefo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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