SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '962c78b1a6486be136b65c1d3094220f6df83e91ced6f7ce7a79e6089e61cab3' 
  AND token = 'Oq53MSOnIXuklkjU/NH6UKug2eBwaZVv53iZKchxmzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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