SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '120f202640e2cb985b3d27f5ceca79acdb01f1d4fd41a3196e701540f034ed35' 
  AND token = 'h4NEYN5jcQigTMwI3GIU8tJzvD0GTrv7fV89g0re9vU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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