SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5982ce159cee653c7175a95a11c08f51d8b51c73c5cc96c6eb1b3b4f4f97562' 
  AND token = 'QDpbfBAekLI4BCiihZ+bH2LYl0wJJV793KUu/XZevlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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