SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e6c352911aae13c161e239e97cb9e7dabf97dfb2e1fabb58a0f76ffbdd97ffe' 
  AND token = 'X+kGhOTJoIpGa5f2ZXeHBF26Vx3K0H8D1Gcax9rPg+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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