SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '124fdb21409cda7d40852c5525b4a09e92cb07d211d2d05493747b6aedeeb931' 
  AND token = 'Xoe1phL15uGoMmzacGd9nsGT16tIbSzTFLBkOiNazjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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