SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c37aaa6b0d5861d2b6dec711e860f41b132a92f013747b2f09fa642eb313a97' 
  AND token = 'm5Be8CvJrSXw0VLVxulBSBsscfxVYXewvGVzXAu7x+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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