SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '387ddd334a51a57d6d25e1bfc3139703ddf09d63bbe10cd4a13301138f0b12db' 
  AND token = 'diW2Q1IeDIibvMNZoY9Km54T2rEE0g4N9nSi6KBIBE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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