SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '596fdd4fb545d2c7218bdb4f9c040b6c3019aa98f350a9a8089ee066c8bf3d9c' 
  AND token = 'hDico82pOGiEksNgWDdUwks/UXWtcsqKgkyHIKyq8bM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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