SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f4539c75e7422fad691f1189e869b574c6cf7522e84cb35b5b01070f04c2419' 
  AND token = 'uNXVqVwY7MolHr7IKDfrUPeTfT5KIZRl8wYoWo/5hCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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