SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd6c1ea37cbc09e6cc344eb6a3a9f72bb0385e1c38b62a74cf7b11887a3fba81' 
  AND token = '/hgK1rRzazJ9jzVuCjNqpU4UFBfiDJB5FrmC7YALlZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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