SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb696f47c39d20db5e1f55045452a8c147d20ca708198e870fe3b9fb68a52878' 
  AND token = 'rkpyKiB0tLpAkJHySzJiiv6HhYsn3hPBawrBjgDHDvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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