SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '673c65033a92af6d918394bce841a759b39ebb08820f6effcf7d66f0c24eb8d5' 
  AND token = '8GokTb51PlVycObFzAgbsBqqpcXEGqlevuq0/IYbX+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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