SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9301ef76eebbf6945296dda8bdd9a4ea755e4ef2255b7751d2b7f3b9acbd4fe2' 
  AND token = 'OGifRJxypQQ/Qy7MK3E0duraTzDmrd/71ylOh5MqBlI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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