SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81ccbc25c8911084647f539d67440e0b1560c245fa9ee19c96318c05adb7b005' 
  AND token = 'lxYBqtSGmqdVOYEsp9RH9X7x2ji9AqhIKp4M99nbAZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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