SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82176865752d7393ac4236633306b54174cb8c75af05586e523d813ad66aaec8' 
  AND token = '7irPvNoEnWuZJQXkuG95iFnYfLF09cKPhWmDjHPfUz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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