SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2d809f7e0ad2045ae8136eddd63ab47e9b2da7d6f34b08949f4d9479223c108' 
  AND token = '+ZkYBQWBdttBjnaAA3mgHV71oZBcP8FFjBTtEHOK4VY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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