SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf86bc28f31f5ab1a751dec06fb76cccb8c746688a513dc7d4ebb143fff21d1a' 
  AND token = 'KZpZK6WfmeunV/CxOkpPzLYo8+HJoPefgrOzJuQMGNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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