SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b92a55b7ff27ee116679056ff75f54e54419b9bfdc124f995ff5b185a81cb3d5' 
  AND token = 'rq3x1cRFzKzuGU54FgO8bhLLsTSOLYOyxGXJa5GHebA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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