SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0dfa9b7696804e22de70a9eef5ec1afb5e29d2f3068fea51d7fb47dc8361e12' 
  AND token = 'ZO46PhitUM2uCaznAn1PtIgiN7A4WndJlG8CFptGcOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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