SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1d9a6aa143ffc7826c96bebb90cde97629851a16f0073acabd6cfa1fc0c8e43' 
  AND token = 'ZVdmg9QWLClBEOMlO3FX17fWO4HclIAxxaNdXjEkT9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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