SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '48ce448c706dbe57f4403874be08141d5b854a3e6fb19b731f3da04a31853d2e' 
  AND token = 'QTakXlGIpJBmnltw+irzTZf1u96B8mkeDgbXIWudYS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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