SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5060b9078c927b44822b4be97412fcab228e991cee35929191b136edfd0bd68' 
  AND token = '55mNnqS2IhdE1qaGo+hDT/TBjmmlBNci7LMmyzOIx3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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