SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28cbd51b611c169c94a9de7fbdfdcca35e27b791ecf2688f1ae54ae2c58c12d0' 
  AND token = '3eNb4KOb9JFVHpYkrXlOrKyF+JybC88BFx6yZoLYUzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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