SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db6bef1e07a255a077bbf79e933af8d14c62ed7fc9406552ea2574fe42daecbb' 
  AND token = 'kqVPf+ufMbYOuUAapjI20Wpz1cLonFS4eBJRnzcp6uI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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