SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e120a2a5eecd650dca28fc4c8e601873d48f3ccddeba0f570d48462395d3d227' 
  AND token = 'anhyvTaDf2tg1Zw4vp9ksgBXIyNYpoyNUwdZ/eDoFq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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