SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef072e53fe157e38f039daa637433363c12870a53b20e5bbec9d8dea1019283d' 
  AND token = 'SkLO/AMNCEf7FnxnTC+5pN8L4c9n+CzIt23kWKtV5eo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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