SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '627a93976ee44356b75d040c42da2896078aa31f14caebcf038353dc1cc32a8d' 
  AND token = 'KoAQqWY4mjuLGuHZo013SQLz92v5dMlVh+0nGN+q8kU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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