SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a14f205b26ff8b5276f130611e4f615bf0b6ec1619dfe1c62a4d0e5af16cf554' 
  AND token = 'KzwarLM7+eMBnqf6apq5QwYLbE5uDXjjp7l+z0zaJa4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}