SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea7b4ed12fbf1a24fbb9fd69b459327b9106d75b963fd4716b6de071865889c3' 
  AND token = 'C8/QBCc/U7Cpw7mjXQNgTbLcauU+5p9ZxIdD7zYoYRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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