SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '926a2fd7abcc841939b967a69c58e27e9883f8e92aad986bc6acc86a45231eb3' 
  AND token = 'XvcoVSjc/wfhQupOUFc+gXogJhayWxm6MDOcBf35Wcc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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