SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f17c41c21039f964fb159709dddd144c963f64e970dc632a68797d71ae82f7b2' 
  AND token = '6da9zETk+YQw1KEeedXwku4Z6fpT0PyCID7t8Fx5JZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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