SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4459a0d88f34383a3af188387004ce94357035ca742a7d1f13f5f9c8e0a63da' 
  AND token = 'XhrY/EjZo8/jdrJYiHBcusF/mh2iCjiVnwVV2iqmQAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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