SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd43b1fa58a66eeb7c5dd6de04439fdf98ea02879853aba7559022179bc565f46' 
  AND token = 'TrMrO7nttSKNJr7iUt19G3MpygbaZSvBQFrv5RNU2qo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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