SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f5f6aecb574863cc84adfee2e6d114e64bf37938d624cedf885f7d98397cd01' 
  AND token = 'Avcrv6kCcQNlfN49Mbu1rkIXupnS5lSTgFsU0J39IfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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