SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c2e0a80fb9f3298bae0fe07c8c30f4298f55c914a278b77427a3bff2831b25f' 
  AND token = 'D16nf5xRP+yTLCodzbzTB6BTglwSbAUtLsk9UiEHuPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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