SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e99c610a0c2802a08bd25be5198c449a9566fcd5e0b90a843f5b8b5ea0eb96c2' 
  AND token = 'DJu+Mtwyr87C/Lf8c99WPZSl39qgNfuRwmHDUyC8M30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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