SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc6b95839b3404d64969381c57a0ed16c2d463d5ccb14b06560fd2eb08f70571' 
  AND token = '3z+nyaBnWfroaOv9KBzWetXHiCcSns/R3xAs5QJ7KWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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