SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fc8e12b9bd922fd7fa85111a49b7691033240b557fba23c200616f856b8ce99' 
  AND token = '/czXzWIE82HARujBsOM0echqPwnR0fkJTdMGa1n9tqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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