SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f9beda74587c0f859eb5383ee4ef768a393a350101146256430d304ab91f00b' 
  AND token = 'W6qc/KDD0cmHjyLI6HwdY652vqYUNUzRUeA/4wnxPiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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