SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a87b85969aa46e52b4c1d7d0d8d84803216120302863d870a433b918f2adb7d7' 
  AND token = '32n7WjJGnc598X6BGEy87Z1loO9v6TUTfHnRltFeG1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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