SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcded80ee9e2314ace041b8edcd6af8ab374686b4c028374ac922be7125ae958' 
  AND token = 'xEZfQpsKj7qVWhqGPeAU+S8mCMxWgwKaN28edZzvxZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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