SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f249d9c9951a82ce67375f27848b2ff45c10d9c64a57d432f2ae804c8ffed219' 
  AND token = 'DSydrxws/tQj3FVfoPiVWysu+aJe/tzRmdn+Od7TuWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00070

JSON explain

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