SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42e0644829a2ca73c29ab01013fa465f6be5b5ee39bff5889deca4bc23576cc9' 
  AND token = 'XiuXKYHVJKmphZ6JrAEUd+JZHPs8mj8UMTDIh4s/Lcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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