SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '31b48ae46a611361f979a612fc4eca1dbde0de8ae04468d266299f8d1b35203f' 
  AND token = '6d2f05imNMkQBwZljTylhMKx1wnFxk2Z22XvkkE71uI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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