SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '366b74db52a4a1523e5686db721c5b86bdb0994e40a61d1df734935b4f74d880' 
  AND token = 'FF2LSjmuS0rXkPMlcYOSllUiJHZZ+FegxQosfq8Iz1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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