SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44817d36d53b12e1999c2769b34cd8461e7d46d28f22b944170c04c6951d7e42' 
  AND token = 'bA+eTNCRLzHcDhhlP3qL/wfQ8KCbRvqmVd/DtojJOJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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