SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ea433ec3e0ee45d018aca868ada19bbfa07a5684fbdea8315604a6abf88e4a1' 
  AND token = 'L8kUdPHf8QGiMM9uBjG3PIS6qjnvqkMs9wE5uzGOukU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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