SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '045fe3fa666488705e8adf8a4db30ab784d48fa315883bac74dc8941d55d0d95' 
  AND token = '2G+F4QQzSDklgd9X96xB3gxq5kkvv/E7Sq07ZOLbiUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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