SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9517d7c028e35c7052eade8d73fb66694160f252c35446d86a301ae1ae763a26' 
  AND token = 'H2cauuQZC+DxsqJld1Ly+Gp9Dk54OVQOgx0CMwsTnSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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