SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '715b9e148953b38ad36e3fb58a2cd6fe11cbfef1ebe3abc50898a494fd29087b' 
  AND token = 'D9SVcGCejyHzs6aT+zR9xgbcSdgu92jALfG2FddH7+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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