SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '784cf54c7ca53f8ce9ee8100ad690a3ea36f44ae16991f3b91dd3f93521b07ef' 
  AND token = '4+7FiYxkX9K/e+AmrYiZ7CW7QFqgNLpFY2fuWNPR9w8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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