SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f81c81da7401da29ada7db95c42b1cd964f5b285879d6bbd10ae794e2e540026' 
  AND token = 'GCyi9jSlYgYBL0HQMAPZRtLNACPmsfXIMVLfBVEfPBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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