SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b476cfd076d78b3c37c44bd4ebd0b54d7a7b7c47f605b6ccdc9d778bf0b130e6' 
  AND token = 'bzH+DLPjE9JX/oAs5jT+zv+5f/udYb3mHQ/szrZW7ZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}