SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14a9169554497e89aca854831d93b4d1dfd4f5069fb2d20e0a1ead6d8bd69c90' 
  AND token = 'bAg8kVAjiCMvZd4t7LsUXsqLXORgOMbNCa4admnsP8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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