SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f8125b9b3ec37343c3ef0774a3e36a2d8fab488ca730f997059bebeae2400983' 
  AND token = 'lplf5BZ3S0L2qiE7lCT0x1H/8YTl8aM99np3eCTQQrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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