SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b598af98dcae042999ea217d646fb7fdfde7a87fba43b4edd91a3e9ef4c13a08' 
  AND token = '0OoYlhIwsyGXyJQDox5RC2OBR0nmZjgv0Rk1C0jTyWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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