SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6596579a4522d1a3516bd63d2b5a91f88deab91900e1e8fbaa8c5e77a7db43b5' 
  AND token = 'eQfYqPCwr//L8fiUbVdJwKY0zopZUmyXTSAy9e9wvuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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