SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '520589c63552390866a676ae97417a7ca97ac158b2cc6f7678d756d580071ba0' 
  AND token = 'vDpnLD71ft4amhhhXHaz4XKxp488hINperJyBeTcd14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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