SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42e9ddcb3e165f366094716dc42a78034ef1316700c160b1064b2763d92ad3a4' 
  AND token = 'HT2xc+fui+W0CssUNv2+gKz4xkm1ET0UpWkvZWRwR1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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