SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b943e886b0cbf4d1c11c9f2d8fd613ebf86429dacf2082fb5daff9582606767b' 
  AND token = 'oRr1MoYKsAgWpfLEdU145HoRcU6D0GfBcou1lJr6PGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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