SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '925caf2411821f5c2199c212fb1a60c21d8cc2fc6e1ac665838ec977f1b5c549' 
  AND token = 'rUWTXHqeiKmCZHKKtdAAXc33KH2NNRkzW48hBwjFXu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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