SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '448f86948023c04c4c3db468d95e7f1e41f5dcfa85d997152ac24eb92277ffe9' 
  AND token = 'yWtwb3gGLdSYRvII74HR8RMGXiUHDo31PzCReMd+DcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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