SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd4e9f25966ab99749408fc6da00f1b3ad1dc0af8841997687b8e656f03b82a4' 
  AND token = 'AcB+E5tvTWl3gsC+RXSdHUl4Tw/fEhw3s/zGyNj6nSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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