SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8e5c9bab07452865934fdcf81fe43c536352398536b262575b282583d451bbb' 
  AND token = 'COj5u30MKwSq/l6cxuJzVBM0ZcmfhqrTC0t28e/MLAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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