SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08f3c33bad7242e1ba04541d1f0a4ae0ac3d79eb1b9f74a4086d52ab0dedc745' 
  AND token = 'f/p8mW4acpRBta4XSJbUS1kTHcaJk1/1eHDcU2BARug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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