SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd64e3d43dbdf23fb9206c4da3c83c97fc6f7804a362311279bba5596c49c6913' 
  AND token = 'gRuMrE9p8ysL4Q3hIEHfP6hsRZHP6u4K9+gzsVA/Ko4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}