SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aac248c228230596612a167801bbabeb16b58122642efd938433d38b0e1142ab' 
  AND token = 'oSqWvngRIKSf02ufsTG+Xh3ZJ6a+EtLgiQ/bb1sNT00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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