SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '891220b5f3d8d874816126e20002fa4f5889839c13e2f45b8afe567254ff4e1c' 
  AND token = 'ZQkw1JnsUX+vwgRnzBykBVz00kJs3V16ZY2RUGtvOyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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