SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4b2c6b0728b05d35427176be2da4bae09cdd692f1af1848f1e460446fe1faaed' 
  AND token = 'ZCYYJIxOyPJ/6lB4xjmoWMfg0S+fglFfuya3qBokR8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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