SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '65a021f4ec1d55af5dc77644850299e93ada3d6c2851963491218720750f5acb' 
  AND token = '8ZBa+OKIuYBmFhGmTw+TzF96epWOdwbYTZ3+HFIBF1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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