SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd67349a059469284a048bf7d0d5415899edfe7e92e2fa30bdf3235807275567d' 
  AND token = 'UKaqXPROAvVTYW5AddN4+5UPnWcSTqnP9QuEeqU6QIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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