SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec3667c0a5574129a37f266677236aab6f4f516933c930abc4825becc488ff78' 
  AND token = 'BPlvA1GgCoFSTU0UGLX7jqaWc37n/9hkyX7myxmIzMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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