SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fedeb3d4ba9aa1946053525034264f58f2c17fe2cf9f415e89becb4b095fc18a' 
  AND token = 'wcratZ5twjAqWM8TGUracF7Otd7Ub0qRPvte4Liu7kI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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