SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dd8f06b765d5f588bb9352fd09d21a92a6132c05205f7ebdd5a50aa937718e0' 
  AND token = '4sJFOYdWU9hf+1NJs+MqakVkBNebyY5420M3ESFmRVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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