SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '968eb01d03dc8bb1f812e851c247014920b18cd5684b63ce206e59e0548c6678' 
  AND token = '/+OZodsLKoJeQAfIM1lVbF0R74OLd3SBLomC8YfyqTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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