SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b21da94fead0b04c4636be6c72ba5b5726c3be7f581db2638fe6485c9c5da8e' 
  AND token = 'BDfH00wtIynvjgXRXuCLWQHROWlzM2mEHGXq4mF7jxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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