SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81c100667ac60a04fbf17117feb53bdd4fc5033ab9310404a1ea8763d9eabf7a' 
  AND token = 'VPWGh/9TUujzhqHBYNE3ozWEHZjjD7C9YTqpJTgEx38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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