SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cc7b6ad1aaa410bfa06fd0f174ff0e3f30224d5ae7a4c05649331c97d5f09a68' 
  AND token = 'Gz19/DWn5JBSGZx9cD54H0ofBvidfKMwTEfyzmyWlQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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