SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e2ba601d9acb203fdcbc544954f1b119a130395838f057278ddab076f41ec4b' 
  AND token = 'pUpZiWqvnR/DvdBeafTrgZhRDeUM/W7MSwaBqPc2w30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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