SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4346da00a9c73f78ce9ea7caa410a27885e330629cf1e83c4bb7d6fad814a854' 
  AND token = 'wTXzK2ngA9OC0pv/hgHByVvzbDz58F/f07RQjt4thok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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