SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '19c43fece8a9a4b900ead4dad066736ed0db2720abcbb012262b013fee31118f' 
  AND token = 'h5/kjMljJForohnJa+1DLqWl+szSKJ4K7Zh3cmgCMmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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