SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ada23e264c1ac5ea6ba95bff60f7cf78a09a04b8159426576eac079cd494d15' 
  AND token = 'PXmFqCqdUgDbO9wIt+UCybISvTSP0Hlcp8fFqyrYwz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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