SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44aad729140555bb9d44b5588fe54c336de1eab9c896c2fee0dd2949669a827b' 
  AND token = '/NEkJmbd00wZBsGKXlpTh2/yt/eOj0kwQzRRsoQNmic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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