SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b4c8af7aa4826b94f72db4510827c41da23b9b4f1f69bdc8c3731feedad3be94' 
  AND token = 'SfsxotEBXkzNz2Iw+EgwCuNRMhknAKkjaMMyDp9bSVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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