SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '20a8b818ef10d0486c93abca6c4edc31de546cb3d3177917364770efee5060cf' 
  AND token = '+ttnJiNc1d8BKjlE1SvkcOQmJByg2YqZJ8TI2oSFWEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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