SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3caf69a66d0dcbbcf033bd699f100bc8ad511bd51e201280983e11d5bb49e9a3' 
  AND token = 'Cm1hknFfHwb/2aiQtnVqzzq5WAo3qHTKD4O0ZXzkv6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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