SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b00afc66344fba217b812a73ad3718d390a9f51b9733fc99227dc51831f2f0d' 
  AND token = '+K37hy2eKuY2m4xdYm/w8XYaHJpnmIZypAcwsN46hDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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