SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fceef2cd13e7a01f33a8ea9b18947e05098c6bffacd0a3e3f06ff34587699515' 
  AND token = 'mtsSqD6VUMcY2ztdoWuBBYtSBY3DXGNX7uvvJzRnw9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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