SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b2f0ed819c4be5f6c1c0ad39d081481ef099ba00944fcea17c7ec8bbb9bb43d' 
  AND token = 'xg2dyWoX1uE5GCvO28IwS9TMOQkMKlMg/oYOAJ64O5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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