SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3b824edfaae277e6f2bfdb334ae5e14fc82b7b8766a5bbb058316b4901ca7c9' 
  AND token = '69J/GAGvuVN3orlFOgxMJuRKDtHeSh/pJ/vH07+hpbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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