SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bae8d1e72cc4c7dd1b06496c9c4d00ce1b2e216ab42d325d01baf06cc3503a17' 
  AND token = 'L3Tq8FEBhDDEwu4CxhyZ63Fo8nbte0ahWgLnNGscSOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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