SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b45d7e1710f51b39c459c3d21b9e06b535a95e52d233f03e4a478b15f797720' 
  AND token = 'ZH2LQgwOM1BFN+s/wdhKNXjDhZDyatJj06Mpdn6GuyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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