SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5818edd5d83c205eeeec418af7a69ce9e731a9e3bb036af36543306cceb189a0' 
  AND token = 'i92FA6o+pzMS3KK5QMtaBOzeuHzYFCVPHaZmfTv7mNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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