SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ebb326ef1daa4038265024ea0173e78ad066c88a75012e0a626bf5e5312ad36' 
  AND token = 'ZbAKEOeQjyAoVCriaFRlaGJPtG4krJLoeaNY6hDlG/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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