SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ff14801ecdcd8ba68e96f9db65d9fa880c796d185b91a422a93f71dad28670a' 
  AND token = 'z75mw/DVjJwaYLXZliQFeF2KzYxR3REANFJnQLozW4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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