SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '003b60d8881a69dffe42bae563ed558f7f00d63a8c20aa8b00e316fe4e598549' 
  AND token = '8iWicRbNN3AaVrD24d3OyKjJ8VkdEOMqCKXuxx5vxvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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