SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1543d6813e5132d13593201db333073b90480758514bdd816f78bcc55727e148' 
  AND token = 'pa7krM2cWKlZxbQsCFYD8DwBjzDtBHPLzMlkMrRsUjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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