SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '238098301f3b7ef4576aad972c13dfae2782322ba4c76ebcad39bf1e7052a67e' 
  AND token = 'zw7eOjb3TcgJqoVL6TFcTpXI0uOm2E7CmxMSJPHQujg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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