SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ee783b8c295b1a565a4953aa74c4f090ee2e7910582798c3815b3c17874d7d0' 
  AND token = 'HwVUEDvUlHvVHk+lVjgXrkgRA6m2hR6sN+oOKRIP+48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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