SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '115405434748553664d5e046c02e21c81bc7d358cc19ff06ee53cf9bd93465e1' 
  AND token = 'rF/CnCZh9PoKMHP9Z6BxyF6rfWF8UxYV1EDdyiIqjjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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