SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3432c7765f2cb4c2d94fb8f880c95686727c9f1e24a13a9816cf3010161e519e' 
  AND token = 'KIj7IHhSzkmVi9U8C0rfTgsvyQ44DkBAxtE2cjbuL2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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