SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd7f6c6fefe574005362c9a952ec7fc53e72344e0fd0379dc4c70da5c465f952' 
  AND token = 'I6HdbkdFiU4+LLdeQjibPj3A8ZGHrneu1qyAMqUc9aU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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