SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18840149d9317b210cee8ad471d152f394fb220d207ee6bf9ef2f1941a4fc8a4' 
  AND token = 'Rp7jkYzhGtJGZA14BeAuIHMgjKTRUqDw4rOiXsHpAho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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