SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d3528c51b88fcdd54b5f7431903ac4b43238316fab4e7fa04e18b2b7fca383f' 
  AND token = 'WdqKLIQpXYWCB6hoU81n19C7hUatRj1O9v0mlGLpQhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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