SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '064a7adbc5dd9189c951f08796f3b13f9df3a67967d3f842f040562a07845276' 
  AND token = 'JKfNbP3A4MD0wlKZFtHK+v/kbaVmcPIvPgl/9+knjPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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