SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4adbc96fddf71446c7ce8070ac41018403ba74f690555f7315cc0bc09406e0cf' 
  AND token = 'ywahuWUT9Nxtxdb4b5iREB7MLFBtTdxFbazMMjuCIR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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