SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f512a4155baeb62245f081936ad96e730864a77939bfdbafe6742939f4fd718c' 
  AND token = '4bwHGen1ww+IdcismvB3HQPQKfbKxJqZhEcJdbrM7ps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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