SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bc77843b8b4da35d26c43b7fb05b095fe47e8fd318c2a4188003cf6a89b4248' 
  AND token = 'nRH8PUhZ584scxhVpyxE+5whUXmWWf/9lCiLdH0+aOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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