SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '76df95c0e03f53fd7588dff08cc5029110239288420d0056884207f2d41d69c1' 
  AND token = '568BKzbkrnjPbYZ5TjA+oQZ1MX/HSMqmgYTW8c3ZPEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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