SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb8ee8aa9655f11754c4f6e666fcf5483d5d61b78bcfe93d905bc79c86de16ec' 
  AND token = '3rYbdgsUZh35MqtZZL+0bL6J6FZ5PuKw3H0XYmBw1xI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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