SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfb328959640b7dfc63e954ef77771d4352c8abeab04dd050a64d8b87e7357ea' 
  AND token = 'bxBO+MCojGIrwtmMfRm7Rftq8HUHZileRheEcscrjtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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