SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74f21019b03a2955e1d17a70066a9ae2ece943fc2faf437c8d7d0fe0645c2f5d' 
  AND token = 'DHj54iWl4Ig6IhbvGO1ZRxdaohpKVGKNdcVJ9FkTF6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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