SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '455a2fb93c018b3d398b80e8c83ad8383f4c90d88141ca244919cb236489d0cc' 
  AND token = 'M5Hnw65SBh+3PUhS51GOhXgoK/apE4yyYsnylD6lz6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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