SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76e8121d0f9751fcb38a8ea25b81039e74ca519adef433a389688f1182f37215' 
  AND token = 'PeGp0cq/6Ue1oNXQXJQeFEXCpZf4YpP1ofnYLOoc9VM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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