SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1714cb5cf2d68fadcc3deb2981ca9b5e829dbb2ac3300048f934297178563a84' 
  AND token = 'VUg+0ityjyJWvH1TLwadz/ZTflN92/3+KPrYSxWfA/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}