SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83ff05cae3875fc4b32827d60d52a797c72cdeee2fd629370300bad0d866bd4e' 
  AND token = '1/BJ46c6R5nQyfNoVvjqZUYFWUAQIGNx16NUzVYOZ2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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