SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b917fb84306ca467d486552f84d2450ef03623d975d80d54c18881e7dc0c7a6d' 
  AND token = '2QB7IHbZxHkakPtFgUYfcEzeHz3GAMkIC588uYQr1o4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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