SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a76b09a56ce447585f445f6ec6e6b302b536bd0fc1e8c2f0647c6575e45a920' 
  AND token = 'dwKtHebcffCJCXWHm2920PgIC68tTdZvRy7iQl1GKrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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