SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '392042d3ecd5b5dc498186f65a36965a8c4024d4af87f17b83af605dd86c15cf' 
  AND token = 'NaRbC4s6rGajt3mqa+7azhUC2wXq/oSaazlQ4Yj5HHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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