SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2ce8b8e9643f92d792ea9bd4ffaa100f5432460ef12563ddd54843e8e4da9bba' 
  AND token = 'aHo1bJRHIWZ+8J1NozKDaS4GU2OaCElZHsKdCrs9JXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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