SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ff68fec6b84a58ab5f7dc5546dd83c410735851a72144e2d7b543f65234aed3' 
  AND token = '+Uv8IP2XaDv1jIJEmr0q6S+s8UxVwVmK81PBYeD7pqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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