SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af52cd051391278d461bf3681066a3871a3e0a234373386588b91b979644e57f' 
  AND token = 'oOEl64jVaj2UDX2meui89Dxqz0WNKvFrXL0nGIASeKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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