SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '384eb84819de688ce9d5f08162f52ea85046e0155e8bcdab376de10e6a4846d2' 
  AND token = 'ojA0i6xvFdhVwIrC1B+bLmLM0PMJSfZeNyGBvy/7rmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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