SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36a2aae56bec4346c2ee30e1a61739343c50bed543afcf66748a8b7b6dcd5f63' 
  AND token = 'mTyJNh15GTNRapMz0NYn0tdaAp56XQiLfWAXyTRwgNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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