SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c028470b438a9c1aadfcf2bc95353bcb47efb357ed1740f6137dff0842d84ebc' 
  AND token = 'e+rGI8UtBZh+VHu7nffU5YYmTo6en+LeOywiAADlLNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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