SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3ad24d3b191c2fd8526ae91d79b6dfcda2035805e511c16f5932230b5b19939c' 
  AND token = 'FVcmBVXkz9Mt4w+XYYmwKpdN7rfmx+/5EvRUMtMKl5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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