SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '62f77cf7a49178377b103fb7936b48339284059d61d84203d515a55cf257e8b2' 
  AND token = 'AkZzkh9VE3ClLiM3CFH6PrXTwtP70JQvVC2Wkz4OpkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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