SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '898c7541168105272edd76285b55c83ce692209852cd522da5d70691d34f9ef0' 
  AND token = 'cusLQsw3+ubozTcKD7G+L4bqGrzPuUikbN+zN/+vFzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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