SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dc361e5a3346f3525395e1bd331a9ee9aa660d19eeaad823d269cd6f8344914' 
  AND token = 'BXlfF9XRV0m8zOAfIEk6fWezpz3TXYWBPeFtMEj8zXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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