SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb5d3b7ea3629e37ac10608cf9c55e776306f7bccd476f301743a3ee5864ba1d' 
  AND token = 'Sbg44vB7FgvouWMNQmFH08HDiuZZjU8bCbdshRTaDKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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