SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7817cb82af74d1151d9d2a242cd25a6fca5d78a323f9c4001f54135e3922e64' 
  AND token = 'yQwWfVnfYZYGZh0zkyKqUHnv0etCziDkh7jBoIj6Pb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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