SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89c0dc43b94ffcda686a0ec760ed7044ae33992d63121e30dd47ab8779df10b5' 
  AND token = 'T2kvVPngH+ADQr1dmUZOqqMJAaYGhlXjsMLh11SZTp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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