SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56535fdb3e1f91bb3a00be7c3778edad8d5c8dfacf3148a4e9501324562cce18' 
  AND token = 'sEf8sMZn3723Nb7tvUT/89tyiKSqDdacINwkgqfsl1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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