SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3953856453556882e98a5bbb196b1a279ef5f086db503a73d2d6440a2558ffcd' 
  AND token = 'pfsFHOIJ6pdZpnxqrTU3+mgzefS9Lg4/7D2YhrXCLyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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