SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fb8c273244ee0d5cfc133042dcbc16816ec28d6280aebbed82941a63f4d8739' 
  AND token = 'czVPmn+/5PRzm+DHxd9EmaCzgeJYbxbYmBEurR0DczA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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