SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd64af5c41cab8663bafbdf6357ba897bdbcf50e4fd80e11c36663f086a61960' 
  AND token = 'TCDfoPokvQMiCCEcG3RWrNKXT14eZvNYWVUOl29pUdQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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