SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9a71e7ffc1cf311c59e7a1f51ce3d6d27dee4e4d536126ecc683586ffaacc074' 
  AND token = '/MMpzvwYnXk020PSkC5PL0H168orWocDumFpWN5F7Ok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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