SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '818cd1fe4662857c11b7a537aba6a8370504a7636553a609423b57cae7fdd761' 
  AND token = 'LNFPnStnWseYUEPUzY6D4MVzNXkcDZIFy8JygSXx8+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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