SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f8a1fb4ceb8c67511af52f3a0ad74c054277a9fb8225c1840b773611ccc4cf9' 
  AND token = 'slUzk8dxepYCNWWtQmO0bzjnLpE8tfajAjUGe/KE9xU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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