SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f3206b6b366b15ec8fe5566a79eed6f7730ec0af92b79298b617b12763c46472' 
  AND token = '42kRmdoz+9KS0hESsiosqdRg3eN1w1nGIkFTG57xcEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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