SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6085b82cef47cfc7b44df5fac906a6a8d7ffd28d36fe5a274edbc47f78032cc9' 
  AND token = '0XnNdDkQtqNmEIi/eqEk+Iz7orzyXrMv7TCts0w/agg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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