SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd626e982fecead78f9bbbe51238d488bac3c310c800a389517606d4ac08a1a5f' 
  AND token = 'm4QOK5IeNmku4oKpweRzVJh9dKWGXrkUe0ZYbEJDugg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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