SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f01bebfae379abb66f6e55ea2f626bf4d60c626731c7f256da6dd8b82da6436b' 
  AND token = 'AvNgXscQlWPqsUEvtl/VZ+zalTs4AhS2rzyjXUA3tpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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