SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6200b9c0f28dc657f261d566b27c9cbe3f918d7a1d4642b935924c68fe126551' 
  AND token = 'lWvUOvG0SRJiqtLsWtcKPExb9RHWHcwj3IkARctK8Yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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