SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d890ff6f253d6dc4f458b17a5dbb8f3748685258397e2207465a6209ab16ed9' 
  AND token = 'Ttai/CByTSMSUdJnrfJoyNyUTQnHei+ZQ5JcvQfDpY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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