SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57c8c6a797415657a0607f9fff7715f8b7d1a842a00c86949582ee2f4220ecce' 
  AND token = 'Vg+QXmw4pRHBExZW0hFm4ZK2whPxiIwVovAZhoix7FU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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