SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b801e405bab398c3951916ab03572b71b4e07f3388e281376fa8b63e2b8e75f' 
  AND token = 't68Tcdxd6XgCt8dZ0qeOkUMwdoJlN2KRCjD0zIYNQjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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