SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed4cd843c7e6956e6aaf6b2aa4d084f0cae6f1877565e9988762461ab94a3eaa' 
  AND token = 'uUo7DnaxnwFVv3iRawEu4LFNzhALV+hzK5prhBIaYlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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