SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '286edd19cede550d4dc991fe81610c2dd5e90020b1a7731d76e13ef3bd0d1468' 
  AND token = 'PxxY1H6b9wYzOXIyBLapD4zQw6XY66H4x0o3BkZQzec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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