SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36fc701ae72dcb1d266eedd1b4afe4c368e8f4daca5c29527b2bf7667609f386' 
  AND token = 'JtocB0FazBhfr/8ZKdkSYprPxyMPKC52oKX5TwKQXHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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