SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8b349f12e3cfbb618cc6349fdcc1d61b03dbd0e73e52b20d04ff6094a83cfb41' 
  AND token = '3xwX4MbOVS283FV2tyb7F6MJf3jzc5nJVWbrSXNHWy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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