SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '78a1cbdad1b182d272b09876e67fd0f440236ef84d46f8437b01db97869c18b4' 
  AND token = 'CnxgAtixnhauVdkyCoO3f7iL9rwP5cW4wu6uoCXGoh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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