SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86cbb23589dfde79c0917072367c93830729b4dc9c487ddc2f091df5dbb4a6ac' 
  AND token = 'hfw5Gu+JKqzYphwUXtWvRtRYyAz5mWj5z7L4hA1Jd48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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