SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83851f9c713a4aaaacf3a7cb56dc0327c046ed1a219feb2e9d30513c5efff020' 
  AND token = 'fZk58F4f/KnOyAK3uENHguS0tJSVoJtVx9DVWQEFmuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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