SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '305e990e8cca3b854491e0bd9f7667f5fd687689842b91517214ccff51adc1d8' 
  AND token = 'eVIXo26Wd5hWyfrkOLKhvQKIFipfzkWsNBzHNt+bB/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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