SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb6b0d1ba4ef92dc850caabaedc12296db78a0cf42b73106721c464bc23d9905' 
  AND token = 'bAPX9c6FFvzt9ThLw0FyLt+D+6Oz2FouOUYrdPbp3DI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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