SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a3f243fa1865037922ae9e6acfd903538b4b3f4db2890f3bbab3aca690e691d' 
  AND token = 'PUO7hDx/V6D89YXrGMVklohq8TZDZLxY3pKm67SlGMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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