SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '844908d0eea0bebfc81c88987697a8d67697edcb7ce044206a07a659b19c0989' 
  AND token = 'zHo+dyVL42xYiXobt36bfCIzFrzJZiKzGjx9KcqnSLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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