SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed71d21eed2a0b4ec03e72b37c70c636dfde8230a7eac62896c54e499bbeec97' 
  AND token = 'E8UGAHF3xkyPIgFeui2CsMqb2OZa+aLwUtdHPotjMe4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00074

JSON explain

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