SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '449c185df890a32693e6c17c710d45bfb0c2dba7b4a8d9a3247ce2d61b88b6ef' 
  AND token = 'TwRsUTZ+AlgLHRh2/wg4T+tKeIgZp7tB/8aXRiGKvmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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