SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7791591bf424203f3e14487c6bb54877ceeaf848067abcfce01e60bc02e93247' 
  AND token = 'B60wWoCIiztsQ2fihNklz0HO4B31NB24VRCMTow7yC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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