SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7aefca8e15f226130e1fb080c47f374d09e4a6067587dd24ece3be00325dd76f' 
  AND token = 'kbLVw660CzDRwt9xe9X5Ic7X3vYO9MyKRyBCKmehcxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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