SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9a860d45cbe16ebce0acb9e395cd1a73285730fda600e35802e8de963026c45' 
  AND token = 'xhu/hc9YypFQtaIEFVrBmOqjbzuUsK7nkcOA+3hBY68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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