SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71fda4dadcb40abfb1d211de0f2689a4fc7df071582bb3156c6671d030127d43' 
  AND token = 'QTHWePq6gTU3k1JwCrMZmKk7mc+3HwL1XvqnckOtfsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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