SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15b39091348bb1ee3f7b7aae6acb5be48949cc543e4d9569c282e9dd3cdfc68d' 
  AND token = 'yRHXl0bxQzzvOAhIEEHLkcNWWmUO0rxn+1thWViuanA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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