SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfc146b14a847ef1da4727926f030e40455e93f016fb41e85f3db16ce5a6f9a0' 
  AND token = 'vdWTU9jZQhOK52ulF4GRHARumSLwcKpwY0UGpf5q+DM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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