SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e98ddb460d99c854362019bf14a11d8326d4362b12c743ae7c61b57a4ccc104c' 
  AND token = 'DOjmhY/vSlqtM4Wzm9Svg0Kda7iNuwuAaYfPLTZeIpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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