SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5f8caf54529b5cf7cb3472cae082c90c0adb69834f8f470247d18cb1c86ed84' 
  AND token = 'wT+nuLkoePbLafFPSJXHdb/LFhWvf6J2MBh4J/2DJ4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}