SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eed0d315b6b513524ae172837b8e05f569a541aa7d11ecbc0f8019746582e53' 
  AND token = 'agw2LqlMKfeHrKrgXj1T01CjDj2Rs/EKcT57Be30VKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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