SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bae5324e93d308b086b2aa1bbd64341a7cbb423e748b068891fecfb8566651e4' 
  AND token = '03sPZrwvAJfLvW7Wk05ZIPXH+3uhqTh+cZXuNnMe25Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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