SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a10b7b86e5a9cd283f88f9c45da24f9a3f075feafaf99d347d12f867c9abda2b' 
  AND token = 'izF5lrCYi3VK7LbArXh377JnGmKzT+9LypRnu2jRYC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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