SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbb6d8200ae222af702245f04d2c183f61c0ff1c2e6271cb3ab771ea44f6238b' 
  AND token = '7fwcYHwwwaIXOJ1/f2MfEeqZRf8xOfBrlhb+sLHu7lI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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