SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bf3af92518d36e2308644e6b24a4ab2742f17296e7c176525f7eb97f781ecf35' 
  AND token = 'Nrg9vmZ6GqQ8Bpcrzft7Liuq3in7tfvHPsJfbaXxK80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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