SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31b03a33ed86cd8575db64901d7be9d601e437fdb0f0691de015151369a6c386' 
  AND token = 'rrvnfG9NMvqTkh4HNVsDhi16zzjl8C8sqiPkbuCLcek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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