SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccb9a11ce5547e922ee84ba2ef710b8861843e67c16909fa4cb185d5489b1ade' 
  AND token = '9TpUTIVcw1m/3JZVGjkFXKJjggeGIB/Cb+zlATAIX4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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