SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9a227694ba267d689162737687ae3d41952c98a1c93c354ee18ad89f747ee2a' 
  AND token = 'FD75AGbskSilPQR3n3hpXbjo9iWP3ZmlGpJYIpincZo=' 
  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"
    }
  }
}