SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3f0dffd413079ea9457f33a8f480f9d3ab9f494eb8898ec003aa28eee1505635' 
  AND token = 'fWrWr+PTOWQg9hRFIYSHh2zvRjQJhum8+rfhB8MOxzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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