SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4a5605211592401ebbd95c1a7c3843e796645b836786d0aa305e0b741e6aab6' 
  AND token = 'w0KHtBCK0LiEg601g9qMCTpo4JLMxnid4PpYVTZhiSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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