SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09e3a372e1052853d8fa563ee919ba6dd0bbc8a265172af458822e45c1d9badd' 
  AND token = '4GTF9GtXZiPuRegZ6inNrMs88bY4RvWJfCb2XtZZ4Mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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