SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '415e25179cd6df642c262df7d4bdcab3621f7dfae8be2266992a6c9642487295' 
  AND token = 'hZ3fGGvGHxwBAj+S22RNvDi31pLHZPxixKv25DX/VhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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