SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '756ebd9460d23efd5f0af9e6f7ebba25b6c84bfe9293467f27a426b93ce94174' 
  AND token = 'vNk9isONGFJSFJitHkudkxWHcarM5Sm5FXvV64JtF/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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