SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69e708515e0b930182dab3282b105d34d116402a675c1641da5ad2ef8f9c4917' 
  AND token = '0ZYSHDg+ZEpJQkjzBY/vNYW5v4gg+8LIFeOFHq/wM3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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