SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce8f0a43fe388b50ae1233cfe926cd80d431480d6339600729dbe3d355f0fb5b' 
  AND token = 'z9zFEwcSSXvGcLTl+S+xN34DNi1WUNKS+3xFBsRrEZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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