SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '776628163d7df56a689a508a34a053206bb648d28cdc523258dd8112d4f3eb1f' 
  AND token = '1GGKZu19jLMq9+/dJKhPe1S2xhuz1p0Bq7wJFZsUk3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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