SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cb87ddf8f9b53ed409644074eed6d91c1fb377ba5bb08f2db18218dc80740df' 
  AND token = '3qCCgGRwb/09xdQ4Nqd/GxQTn0IG3mIUivaBPSUyzsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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