SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9eb630eebdc6ea1d008be57fb72c2693f977ebb5dcbdb69572232d24615b3df' 
  AND token = '654PzFlPNxnLYvYdawDVfwyM9OE8yZBl9QyTqjaGARA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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