SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cb8ec4973a8ebec1e76b3fe08d3b7ce698b5d8117a09b813015002862709390' 
  AND token = '2TbbFktNVVWFwUOjswkMte3XyjOoWzXfhZ7+6VYDyss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}