SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf89e3541f31f1de40cd644c9ae60248b907234956d484edda79b73c575501c8' 
  AND token = 'fqHLSmNJTyfrMbr6TuWNbivcviDkS5WaYkzoRVVaBCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00072

JSON explain

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