SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5a35c7fcae639d7cb49f5ac8bf9bfdaece31b4b102a18ed21df682b3635a0b8' 
  AND token = '2yLnSrmoMciXADgfBu+I7i+ghYoZGGj80y9KuB/6yKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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