SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef32bea358a449d0d84c2343c89dd22efd62d415b256810b97b910af9043765c' 
  AND token = 'VMuSxRo5AMmKpW/mASAESBFCnFBFrDHWBBOO2+sezkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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