SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7611258e03ffe6345be368da2d66564b26111037f8c434911f6f14d220f7bf40' 
  AND token = 'xxFbm9BkkJlhYwrZf0Q1SXMtIzBMqjdRGDaW5ENLVEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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