SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7efaff1358e5e9a42333304b746444eee4d915188ac1c1c380d740c130c557ff' 
  AND token = 'wi4tfUvPyZt2GQ6adTJ5PDalDeIAkASHhcb2KRJ529E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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