SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4891db8bc2210806228a0d9a22fcde068948695e32fbcd53c6adf665f1849860' 
  AND token = '2f6syn5UjukfyT+2mTVNJsiF/mjT6Cm6yip1BXbXbOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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