SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6258bc0d4555d2773e05fc348212fd7297b8444e1ec22b4e7faabec8728f4ab1' 
  AND token = 'wj+wf8yhzc6yW1jZJLKtDzRvXTW6mm4O9FDl1lBqp80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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