SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfb557ba75154376790ef859a98313b26e8bc983e0feb72ea84c8a79d0640c6d' 
  AND token = 'G6nfX+5FeoEKXUCZPzsePijPSqT95GdvF1NHxqgKcFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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