SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81d60930defe5f7ac4255b2e9c232a305ba2a328a5ec9cdd7a1f921b74c49b5e' 
  AND token = 'au6igTjaoWCR5SCQcY+3RfIGUBkFtyhXBck8mCcpbgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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