SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bff9a244b858015a721c845c3b5ecbe5a4c8f9fd51684fd081b152dc86a3c371' 
  AND token = 'D10G2Ga2372S8DHwMdAN9iHtvt6YT7SKzFbwToH1U38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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