SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '404a94f9ad64ec39e107dccb791b9d2421e8c84bb3daef3c98180938214bcb3f' 
  AND token = 'utA6gXT6qYcHYBK/+d0Z6qnsZzFhW35KDJSo1DxrUSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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