SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c831d7cdd6dffcc9521c40c23beec7f4b0889fd0f8455c44ebdada53d3a7103d' 
  AND token = 'nNfG4QRfo5R+5Go2UquHQ/s+ncaVBpmIFvMTPHDH9Ig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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