SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbdc9fa78b434ac98a9979e04525c83bacbb12233d3d4a71867ea1d56cc25602' 
  AND token = 'PDxWoEog2fDh1qqqM5IvC5tdbNUHVF/tklszAJguTBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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