SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffdbf6ccba4bf23dcb114b0db1e72357a427ce0e49ca8f5fde73fd49fd50ba66' 
  AND token = '6ioFVuDa+D/BNX6XAhIxvwtBlyff5W75wlufM25F0E0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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