SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef3acc81a4b98fd2b4c407c9910536ac314912feb95bb8ebc06826be36bfbacf' 
  AND token = 'Iuh1ZgLr+NfDMdMBKQMR4YO3OadPAS69y5qk3TcmhBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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