SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02e57a7dd74f43dc128b9c333813e04fe85a994b742cec41a1c422c4d8336cd4' 
  AND token = 'OxnHFn5fjuVdFNjjV8QVBgT5z2E+waU05uQqzOEJpDs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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