SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b98b152ddf8a7efbd8b0d7d942ca31aac4b64542f434f086985d71836e8444a' 
  AND token = 'jkfe7mnjaSo2Rk2Ooiia7ReLAjKrCgGb46lTq6dJyMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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