SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa3c2085f748e56e717ba51ce7408ff9a1f265d8beab121477a5b47c9928b36f' 
  AND token = 'jQBxaY8rjvBlYaHrmtsk798MCfDN2e1wx0iAyADisnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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