SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad664a409bab2d1807406b6977864bac0464b103beef92950db81ef3b6ec1f1a' 
  AND token = 'MQi35rssvTmwwKyfMXJkn/rQSjEw1zfAgoatoKt2BZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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