SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb5914b9606a705f7f18658db6c617e88dcb4d269b75374aa2dddfd7ef09fa31' 
  AND token = '3JcGmKAkm3WqzEUzuZk1IZHjmdH2dUotXp5W3qV3Xig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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