SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54ebf9f73d145cc2f1191f0cc6ab749c979e885570626512794ee3dbfae72eca' 
  AND token = '6CHKaM6s09MN+lh8pHyGZKTDdt3PXQT1AJpN3do5woc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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