SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0c9b2c419a0bf5be6b0f807afbeb5608397e8d3e3435d939ad6443354690523b' 
  AND token = '/0sN3iNK9i9wtqmzyBhYYobvHkbX4joJuspNq1ThfvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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