SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e511cb2b22b8264863443a52cb91ff2f5cede1adbd9430cac96fdb90882ae51b' 
  AND token = 'r6aruTF+RbiOieALfyM0sv1ZpWfPos3fOJVuWsFORE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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