SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5727fc3cab12523c89616cd482dc8f8cb1e83e1e780836ce425a2ef0741c6527' 
  AND token = '87hBGD7tA9htYdfDoQHvHvbHkC+HHf54XwZyQzS5Dlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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