SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24c788a4638831222bff84cfea644dda2ec3fbcbc704dfbc6462c6e63e063ccd' 
  AND token = 'fJhJJG0X0e60GUi7BHOVOvRZZlBAE6vkeWyDpKNodmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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