SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe6bbef0c4a314b80bce79f3f1438e08bf5cdc57655ae58c8b742af55b53cda4' 
  AND token = 'fh93LL5SYnFJqKbgruKpc+y0nl7vrKlvoCK2o3p2l4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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