SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7b4277836daabbae071a838d6ff5b9364f98e6f30d24e5f2dfa609f9781aea6' 
  AND token = 'PqWjNJixRF9ErGG7zzcJKXUwjHjcTUgHvZovF2DG19M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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