SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8a05636211fab56b49cc3f100ee8ebc6be36458ddaeed7149fa22676e6783f5' 
  AND token = 'tbeNKyUBH0htyp+NxWyHaf1Gzhdi5Vbu4Tp3xUzhmkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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