SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9b20ace4d914aba79d7c4da26d69fe69c53ec47495db13b2d02a2e9ed7b383f' 
  AND token = 'fTBLqihzHqDI6BOwLocN+s2s7g6MKWWKG4fvgY5oBUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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