SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5bcf357b0ee61f66fb7882df2687b53794ae4100339b0e53abfac2df524920a' 
  AND token = '0/dtPX6cyUha1LZq3uQvC+T0x7ZltyUzwMX5FAjQY4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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