SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9fe72875eb3998fb59ff38ac675a43a871dcd20c7a42b2a20526651245224c2' 
  AND token = 'gBwQ7KUUwR3lFFJzKpVlQbP/xoFlwOwyzV1wHsXNuN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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