SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e35e0804ef12bb5fa21c466ff1c070927b0c3917efdad3b650f217a98198ce6' 
  AND token = 'B293Sqqkd0LRxv1AEwc1ssxIxBQjHPvvnvyweJm0GlE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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