SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdbe76650a93485801b3551bd71f1336210fdace21ca593ab282a4215e9d7fb2' 
  AND token = 'hLKFP0m+Fs80SWipORXfaSZ2V/M39sIrOy6w7inBmJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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