SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '257c57329ff858246ef81ad5e0acfce11d04c0f25081c784bb4b342b8fb5e526' 
  AND token = 'WPQkXnC9JLeiPCjYZeHcd4upVODtw+OqWTg5HBWPRVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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