SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8431335b39c26201b9a731587e5c9704990ce9052b4a381e04ecdcd4a5fbea19' 
  AND token = '5WwiiDr7IXjIIYfRIkWNo2BJSOYUiXBKt8UJOhdSL0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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