SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99159172bc1556e010f04b6e834d58d4a9f6c8c04fec3bf979c4192c823a8847' 
  AND token = 'Lt8zdnKKQqjHwahA9lgK6qTa+lx2xoJ0S8bfzw/qKI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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