SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d6ff07eb0629dd5518a0c028a6c3499a95a4a33a30e4da65ced7c16ba24910f' 
  AND token = 'WPsziQOSVlfZeFBAefVq1VDA5Gvwz+XUSYvo0quKcFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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