SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18d6b3ff9103a08998ff757e77ed9a79e9c42684cd30209dad7047ccb979fed5' 
  AND token = 'tU4Nlp58KmBwZsCxbbwgEYJFvxINsg3GlGFkNFcvij0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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