SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '50db97d4d61a5e19d9ccd77e8226d0ec506fe20d0ad7a9100ccef5fe3c34dd19' 
  AND token = 'ba38hCqVqEvzE+NjaHfotf18hcBVXsG0ZeziJi30bgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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