SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48d077e5b9212eb645b239341d480a4ce1d349d72bc1a29887006a298be8fb80' 
  AND token = '0BDcO2cTt8ZE7KFAye//PmOIoayFp9IkTCAoIVN7lME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}