SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '451d62b8e0d8fe1e79e84f41d3b9b5ed8a27f7af273e622e54891d57bc0d99aa' 
  AND token = 'JKIcUrq4H6hzE7HbXzhVaj4qTdET2QfOuEiyiM1l4f0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}