SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd54eb6f302e29feae0d7b735439be57ac234c47f1316f95b3fb395e287b632b8' 
  AND token = 'caSCIa11Z91LjzPKaT+eX21VHHIwe9KyZiJHYYV42F8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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