SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '774f5dd15025bf392087aa18db01ee3e01029eef83f12850850fb717d96e779c' 
  AND token = 'YvsJp09Ei2tv//KFYuX8dKKojPulkbR7t52or6iOJXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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