SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd00cbc973f7fefe33585bde1845b37fc01232e3789b3867f2a84d36edba9c97' 
  AND token = 'DerpG5On5JxbjdEBXph4rhqIr/TmCzecGeFkjPgbFrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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