SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3175dd23d8b7d959e26200034609ae3002508a3ad52208298327247ede51160' 
  AND token = '+u9V+QIUvQBVS9tAAqdoVIyc2+GOTmrX8PW3z7zjzuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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