SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '36896725c467e5481f8b0452861ffce22280ffe737e600b1da700be2136075b2' 
  AND token = 'c6ZN/AQD9xolmQeSIg3Kaye3MrBGt+Uu2DgQXLHq50g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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