SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16da979f41fdf57f11828ccac910f1b8fe3578cad1f8a04012603945d8a03643' 
  AND token = 'AFIl3rfSSoBGLWsEn/MrhxlJnsnaaTojhTXA6R2m+lU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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