SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16deefd89cdb11e1ea4c83e36242bd278d59683062ef9e1ec8d4f756f67409bc' 
  AND token = 'rvG9bTZwXVXdtFnoZqt9RvD6csdMpCI8JE3JEIV3RBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}