SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a8f76d2c30320466dcf8e148c37b142f21994e7925cda6fb4a20e922d4d31862' 
  AND token = 'pQKAbEq2jsLxthkxGEkcK78o3iOH/xIoG+K9GnIASNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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