SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d924e92262ec0da05521aa7176028216e3e53f86ea0e18e843b872d92dff8d8' 
  AND token = 'EZeZTEyWK3Lsvjwc19AHKoc9kntWWdPuquzkeMe0bBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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