SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dd0ffc234e956e002bb4ad50973b719287269f9c1ca6923439e7d1b46dbce05' 
  AND token = 'LVJqBAggOL4XdFvTTXUrEDRmUSXtfI4VOdjaJHYciVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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