SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dfaaa525784bc15bc21ff3bcb9730fbca182a6e01828f828d384afa62109243' 
  AND token = 'hG5UgLSMrxNu9vw0rTQ0MfuB7iZOYNR4m3o2r69Sl1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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