SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd270b6812d127d7198717b4c5d2f35de167c19fc9ab4ca95261f0841fdc653b3' 
  AND token = 'gUj6t+OdaUjsK63WKm+G/z2YD9xsGhNpZ5VsbQTpnbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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